math

A dding and subtracting

within o - 20

�asic addition 1
and subtraction
facts e
Copyright 2006 - 2021 Taina Maria Miller.

EDITION 2/2021

All rights reserved. No part of this book may be reproduced or transmitted in any form or by any
means, electronic or mechanical, or by any information storage and retrieval system, without
permission in writing from the author.

Copying permission: For having purchased this book, the copyright owner grants to the teacher-
purchaser a limited permission to reproduce this material for use with his or her students. In other
words, the teacher-purchaser MAY make copies of the pages, or an electronic copy of the PDF file, and
provide them at no cost to the students he or she is actually teaching, but not to students of other
teachers. This permission also extends to the spouse of the purchaser, for the purpose of providing
copies for the children in the same family. Sharing the file with anyone else, whether via the Internet
or other media, is strictly prohibited.

No permission is granted for resale of the material.

The copyright holder also grants permission to the purchaser to make electronic copies of the material
for back-up purposes.

If you have other needs, such as licensing for a school or tutoring center, please contact the author at
https://www.MathMammoth.com/contact.php

2
 Contents

Introduction ............................................................................ 5

Add Using “Just One More”................................................ 7

A “Trick” with Nine and Eight ........................................... 9
Adding Within 20 ................................................................. 12
Subtract to Ten .................................................................... 16
Using Addition to Subtract ................................................. 18
Review: Completing the Next Whole Ten .......................... 21
Review: Going Over Ten ..................................................... 23
Adding with 9 ........................................................................ 25
Adding with 8 ........................................................................ 27
Adding with 7 ........................................................................ 29
Adding with 6 ........................................................................ 31
Review - Facts with 6, 7, and 8 ............................................ 33
Difference and How Many More ........................................ 35
Number Rainbows - 11 and 12 ............................................ 38
Fact Families with 11 ............................................................ 40
Fact Families with 12 ............................................................ 41
Number Rainbows - 13 and 14 ............................................. 43
Fact Families - 13 and 14 ...................................................... 44
Fact Families with 15 ........................................................... 47
Fact Families with 16 ........................................................... 49
Fact Families - 17 and 18 ...................................................... 51
Review .................................................................................... 53

Answers ................................................................................ 57

More from Math Mammoth ............................................... 72

3
4
 Introduction
Math Mammoth Add & Subtract 2-A deals with two main themes:

• strategies for adding and subtracting within 0-20; such as adding just one more, a trick with nine
and eight, and subtracting using addition;
• memorizing the basic addition and subtraction facts of single-digit numbers.
In the first several lessons we study basic strategies for adding and subtracting within 0-20. After those,
we study the idea of completing ten and going over. For example, the child adds 8 + 5 by first adding
8 + 2 (which makes 10), and then adding the 3 that was “left over”. These lessons prepare the student
for the next part of the book, which has to do with memorizing the basic addition facts.
The next lessons in the book, Adding with 9, Adding with 8, Adding with 7, and Adding with 6, provide
lots of practice for learning and memorizing the basic addition facts. There are 20 such facts:
from 9 + 2 till 9 + 9: 8 facts (lesson Adding with 9)
from 8 + 3 till 8 + 8: 6 facts (lesson Adding with 8)
from 7 + 4 till 7 + 7: 4 facts (lesson Adding with 7)
from 6 + 5 till 6 + 6: 2 facts (lesson Adding with 6)
Some children will accomplish this quicker, needing less practice. Some will need more practice. You
can also add in some internet-based games (a list of online games is provided below).
After those lessons, we study subtraction. First, the child subtracts to ten. This means subtracting from
14, 15, 16, etc. so that the answer is 10, for example 16 − __ = 10. In the next step, we study
subtractions with an answer less than 10, such as 16 − 7. The student practices these by subtracting in
two parts: First subtracting to ten, then the rest. For example, 16 − 7 becomes 16 − 6 − 1, or 14 − 6
becomes 14 − 4 − 2.
The last part of the book includes various lessons titled Number Rainbows and Fact Families with ...,
which give lots of practice and reinforcement for the basic addition and subtraction facts. These lessons
also include many word problems. They emphasize the connection between addition and subtraction to
solve basic subtraction facts such as 13 − 8 or 15 − 6. Alongside them, you can also use games or
flashcards to reinforce the learning of the facts.
Learning and memorizing the basic addition and subtraction facts of single-digit numbers is very
important for later study. For example, regrouping (carrying/borrowing) in addition and in subtraction
requires that the student be able to recall all the sums of single-digit numbers and corresponding
subtraction facts efficiently and fluently. The goal is to memorize these facts, or at least become so
fluent with them that an outsider cannot tell if the student remembers the answer or uses some mental
math strategy to get the answer.
Please see also my videos at http://www.youtube.com/watch?v=XSVlrkBf_Ns and
http://www.youtube.com/watch?v=jdIzuGPRhRQ (Or go to www.youtube.com/mathmammoth and find
the videos about addition and subtraction facts). These two videos explain several strategies for
learning addition and subtraction facts, many of which are studied in this book.
I wish you success in teaching math!
Maria Miller, the author

5
Helpful Resources on the Internet
We have compiled a list of external Internet resources that match the topics in this book. This list of
links includes web pages that offer:

• online practice for concepts;

• online games, or occasionally, printable games;
• animations and interactive illustrations of math concepts;
• articles that teach a math concept.

We heartily recommend you take a look at the list. Many of our customers love using these resources to
supplement the bookwork. You can use the resources as you see fit for extra practice, to illustrate a
concept better, and even just for some fun. Enjoy!

https://l.mathmammoth.com/blue/addsubtract2a

6
 Add Using “Just One More”
Do you remember the numbers that add up to 10 (“the sums of 10”)?
There are 9 and 1, and what others? List them now.

JUST ONE MORE than a sum of 10:

8 + 2 = 10 8 + 3 is JUST ONE MORE 5 + 5 = 10 6 + 5 is JUST ONE MORE

than 8 + 2, so the answer than 5 + 5, so the answer
8 + 3 = 11 is also just one more. 6 + 5 = 11 is also just one more.

1. Change the underlined number to be JUST ONE MORE. The answer changes, too!

a. 8 + 2 = 10 b. 4 + 6 = 10 c. 7 + 3 = 10

8 + 3 = _____ 4 + _____ = _____ _____ + 3 = _____

d. 1 + 9 = 10 e. 5 + 5 = 10 f. 4 + 4 = 8

_____ + 9 = _____ 5 + _____ = _____ _____ + 4 = _____

2. Find the missing numbers.

a. 7+ = 10 b. 8+ = 10 c. 6+ = 10

7+ = 11 8+ = 11 6+ = 11

d. 5+ = 11 e. 9+ = 11 f. 3+ = 11

3. Add. Think of JUST ONE MORE. Color the problems where you use that idea!
a. b. c. d.

7 + 2 = _____ 5 + 6 = _____ 4 + 6 = _____ 2 + 9 = _____

3 + 8 = _____ 3 + 4 = _____ 2 + 8 = _____ 5 + 4 = _____

5 + 5 = _____ 6 + 4 = _____ 7 + 4 = _____ 3 + 7 = _____

7
 The double of something means twice (two times) that thing.
For example, “double four” means 4 and 4. So double 4 is 8.
How much is double 3? Double 5?

Double six, or 6 + 6, is 12.

We can use that to find 6 + 7. It is JUST ONE MORE! It is 13.

4. On the right you see a doubles chart. You can use it for the addition problems below.
Think of “JUST ONE MORE!”
5 + 5 = 10
a. 7 + 6 = _____ b. 7 + 7 = _____ c. 9 + 8 = _____
6 + 6 = 12
d. 8 + 8 = _____ e. 5 + 6 = _____ f. 9 + 10 = ____
7 + 7 = 14
g. 7 + 8 = _____ h. 9 + 9 = _____ i. 6 + 5 = _____
8 + 8 = 16
j. 8 + 9 = _____ k. 6 + 7 = _____ l. 8 + 7 = _____
9 + 9 = 18

5. Solve the word problems.

a. Joe bought a package of 12 balloons. He gave three to Sam, two to

his sister and five to Jane. How many balloons did he give away?

How many balloons does Joe have left?

b. Marsha found seven uniforms for the softball teams in one box, and six more
uniforms in another box. How many uniforms did Marsha find?

c. Three of the uniforms Marsha found were clean, but she had to wash the rest.
How many uniforms did Marsha have to wash?

d. Eight girls and five boys came to play softball.

How many more girls came than boys?

e. Did Marsha have enough uniforms for the boys and girls who came to play softball?
If not, how many more uniforms does she need?
If so, how many uniforms were left over?

8
 A “Trick” with Nine and Eight
A “trick” with nine

Imagine that 9 wants to be ten! It's not happy—

it wants to become a full TEN!
So, nine asks the other number (this time, 7) to
give him some in order to make himself to be a ten. 9 + 7
Seven says, “OK,” gives one to 9, and has only ↓ ↓
six left for himself.
10 6 = 16
In the end, we have 10 and 6. We get 16.
We can also show the same thing this way → 9+ 7
| \
Notice: it will also work if the second 9+1+6
number is 9. Why? Because you can add
in any order. 5 + 9 is the same as 9 + 5. 10 + 6 = 16

1. Circle all of the blue marbles and some of the yellow ones so that you get a ten. Add.

a. 9 + 6 b. 9 + 4

10 + 5 = _______ 10 + _____ = _______

c. 9 + 3 d. 9 + 5

10 + _____ = _______ 10 + _____ = _______

2. Fill in the blanks. Imagine that nine wants to become a ten.

a. 9 + 8 b. 9 + 7 c. 9 + 9
/ \ / \ / \

+ 7 + _____ + _____

10 + ____ = ____ 10 + ____ = ____ 10 + ____ = ____

9
 A “trick” with eight

Imagine that 8 wants to be ten! It's not happy—it

wants to become a full TEN!
So, eight asks the other number (this time, 5) to give
him some in order to make himself to be a ten. 8 + 5
Five says, “OK,” gives two to 8, and has only three ↓ ↓
left for himself.
10 3 = 13
In the end, we have 10 and 3. We get 13.

8+ 5
| \
We can also show the same thing this way: 8+2+3
10 + 3 = 13

3. Circle all of the blue marbles and some of the yellow ones so that you get a ten. Add.

a. 8 + 6 b. 8 + 7

10 + ______ = _______ 10 + ______ =_______

c. 8 + 3 d. 8 + 4

10 + ______ = _______ 10 + ______ = _______

4. Fill in the blanks. Imagine that eight wants to become a ten.

a. 8 + 8 b. 8 + 5 c. 8 + 7
/ \ / \ / \

+ _____ + _____ + _____

10 + ____ = ____ 10 + ____ = ____ 10 + ____ = ____

5. Right or not? Cross out the additions that are false (not correct).
a. 6 + 6 = 13 b. 7 + 8 = 15 c. 9 + 6 = 15 d. 9 + 7 = 17

10
6. Solve.
a. A basket has nine apples in it. b. Jeremy picked up nine apples that
Alice ate two, and her brother had fallen under an apple tree. Then
ate one. he picked up six more under another
How many apples are left? tree. How many apples does Jeremy
have now?

c. Alice picked 7 flowers and Jeremy d. Jeremy put toy cars end-to-end.
picked 9. How many more flowers One car was 5 cm long, another
did Jeremy pick? was 5 cm also, and the third car
was 4 cm long. How long was
How many flowers did the children Jeremy's train of cars?
have together?

7. Write a number inside the balloon so that the numbers in the balloon make a ten. Add.
a. b. c.

+5= 15 + 2 = _____ + 5 = _____

d. e. f.

+ 6 = _____ + 4 = _____ + 8 = _____

8. Add. Think how the nine or the eight wants to be ten! If the second number is 8 or 9,
turn the addition around. You can add the numbers in the other order, 8 or 9 first.

a. 8 + 6 = ______ b. 6 + 9 = ______ c. 9 + 4 = ______

d. 4 + 8 = ______ e. 8 + 7 = ______ f. 9 + 9 = ______

g. 9 + 5 = ______ h. 8 + 8 = ______ i. 3 + 8 = ______

What number goes in the shape?

a. + 8 = 16 b. + 9 = 15 c. + 2 + 7 = 13

11
 Adding Within 20
You have learned many things to help you add when the sum (the answer) is more
than 10. Let's review them:

1. The trick with nine and eight. 2. Just one more than an addition
you know.
9+6=?
For example, 3 + 7 = 10,
Think of nine wanting to be ten, and so 3 + 8 must be just one more, or 11.
so six gives one to nine. Then, the
addition becomes 10 + 5, which is 15.

3. The doubles chart: 5 + 5 = 10 4. Just one more than a double:

6 + 6 = 12 7 + 8 is just one more than 7 + 7.

7 + 7 = 14 Since 7 + 7 is 14, then 7 + 8 must

be 15.
8 + 8 = 16
9 + 9 = 18

1. Write here additions that you can solve using the idea “just one more” than a double.

a. 5 + 5 = 10 b. 6 + 6 = 12 c. 7 + 7 = 14

5 + 6 = 11 and _____ + _____ = 13 and _____ + _____ = _______ and

6 + 5 = 11 _____ + _____ = 13 _____ + _____ = _______

d. 8 + 8 = 16 e. 9 + 9 = 18 f. 10 + 10 = 20

_____ + _____ = 17 and _____ + _____ = 19 and _____ + _____ = _______ and

_____ + _____ = 17 _____ + _____ = _______ _____ + _____ = _______

2. Add. Use the trick with nine.

a. 9 + 8 = ______ b. 3 + 9 = ______ c. 9 + 5 = ______ d. 6 + 9 = ______

12
3. For each sum with 10 write another that is “just one more.”

a. 1 + 9 = 10 b. 3 + 7 = 10 c. 8 + 2 = 10

_____ + _____ = 11 _____ + _____ = 11 _____ + _____ = 11

d. 6 + 4 = 10 e. 5 + 5 = 10 f. 7 + 3 = 10

_____ + _____ = 11 _____ + _____ = 11 _____ + _____ = 11

4. Add. Tell which idea you use to add.

Trick with nine a. 7 + 7 = _______ b. 9 + 7 = _______ Doubles chart

Trick with eight c. 8 + 3 = _______ d. 6 + 7 = _______ Just one more

than a double
e. 5 + 6 = _______ f. 5 + 8 = _______
“Just one more”
than a sum with 10 I just know it!
g. 8 + 8 = _______ h. 4 + 9 = _______

5. Solve.

a. Maria had $9. Then her mom gave her $5 for picking berries.
Then she bought ice cream for $2.
How much does Maria have now?

b. Ashley had 9 shirts and her brother Andy had 8. Then they both got
three new shirts from their aunt. Now, who has more shirts?
How many more?

c. Emily had $10. She bought colored pencils for $6 and a pretty
eraser for $1. Now how much money does she have?

d. Natalie and Eric went to play tennis. They had 8 tennis balls with them.
During the game they lost two balls, but they also found four more balls
near the tennis court that other people had lost.
Now how many tennis balls do they have?

13
6. Each time, two more is added than in the previous problem. Can you see the patterns?

a. 8 + 2 = ______ b. 5 + 3 = ______ c. 9 + 2 = ______ d. 7 + 3 = ______

8 + 4 = ______ 5 + 5 = ______ 9 + 4 = ______ 7 + 5 = ______

8 + 6 = ______ 5 + 7 = ______ 9 + 6 = ______ 7 + 7 = ______

8 + 8 = ______ 5 + 9 = ______ 9 + 8 = ______ 7 + 9 = ______

7. Add and subtract. Start with the number in the bottom left-hand corner
and follow the arrows.

+8 −3 −2 −2 +5 −3 +4 −4 −3 +9
7

8. Count by tens.

a. 18, 28, _______, _______, _______, _______, _______, _______, _______

b. _______, _______, _______, _______, _______, 77, 87, _______, _______

9. What number goes in the triangle?

a. 6+ = 12 b. 8+ = 16 c. 6+ = 11

6+ = 13 9+ = 16 7+ = 11

10. Erica drew a line 9 cm long. Right after it she drew another, 6 cm long.
How long are her two lines together? You draw them, too!

14
11. A challenge! Here are ALL the addition facts where the sum is more
than 10. How many of them can you solve? We will study these more
in second grade.

a. b. c. d.

8 + 8 = ______ 7 + 8 = ______ 7 + 7 = ______ 5 + 8 = ______

2 + 9 = ______ 9 + 6 = ______ 9 + 8 = ______ 3 + 9 = ______

7 + 5 = ______ 6 + 5 = ______ 7 + 4 = ______ 7 + 6 = ______

e. f. g. h.

9 + 4 = ______ 8 + 6 = ______ 9 + 2 = ______ 6 + 9 = ______

4 + 8 = ______ 6 + 6 = ______ 8 + 5 = ______ 8 + 7 = ______

6 + 7 = ______ 5 + 9 = ______ 5 + 7 = ______ 8 + 4 = ______

i. j. k. l.

9 + 3 = ______ 4 + 9 = ______ 9 + 9 = ______ 8 + 9 = ______

4 + 7 = ______ 7 + 7 = ______ 6 + 8 = ______ 5 + 6 = ______

9 + 5 = ______ 3 + 8 = ______ 6 + 6 = ______ 8 + 3 = ______

+ = 13 + = 16

What numbers + + + +
can go into
these puzzles? + = 11 + = 15

= = = =
15 9 14 17

15
 Subtract to Ten
1. Subtract the “dots” that are not in the ten-group. You should only have ten left!

a. b. c. d.

12 − 2 = 10 14 − ____ = 10 16 − ____ = _____ 15 − ____ = _____

2. Subtract the “ones” so that 10 is left.

a. 13 − _____ = 10 b. 17 − _____ = _____ c. 19 − _____ = _____

Subtracting in parts

Let's subtract 13 − 5. First we subtract

enough dots that we have only 10 left.
So, first we take away 3 dots. 13 − 3 = 10.
13 − 5
/ \
We still need to subtract 2 more. We 13 − 3 − 2
subtract those from 10. There are 8 left.
= 8

3. First subtract enough dots so that you have only 10 left. Then subtract the rest.

a. 14 − 7 b. 15 − 8 c. 16 − 8
/ \ / \ / \
14 − 4 − 3 15 − ____ − ____ 16 − ____ − ____

= ______ = ______ = ______

d. 13 − 6 e. 12 − 6 f. 13 − 4
/ \ / \ / \
13 − ____ − ____ 12 − ____ − ____ 13 − ____ − ____

= ______ = ______ = ______

16
4. First subtract to 10. Then subtract the rest.

12 − 6
a. b. 15 − 9 c.13 − 8
/ \ / \ / \
12 − 2 − 4 15 − ____ − ____ 13 − ____ − ____

= _____ = _____ = _____

13 − 7
d. e. 14 − 7 f.12 − 4
/ \ / \ / \
13 − ____ − ____ 14 − ____ − ____ 12 − ____ − ____

= _____ = _____ = _____

5. First subtract those that are not in the ten-group.

a. b. c. d.

12 − 5 = ______ 14 − 6 = ______ 13 − 6 = ______ 15 − 7 = ______

e. f. g. h.

15 − 8 = ______ 14 − 5 = ______ 16 − 8 = ______ 13 − 8 = ______

6. Tom is 13, Juan is 8, and Alice is 9 years old.

a. How many years older is Tom than Juan?

b. How many years older is Tom than Alice?
c. Two years later, how many years older is Tom now than Juan?

7. Finish this addition and subtraction “journey!”

+5 −4 −2 +9 +2 −8 +5 −6 +5 −2

17
 Using Addition to Subtract
From the picture on the right we can write two Fact family with 6, 5, and 11:
additions and two subtractions: a fact family.
There are TWO parts that make up the total, 6 and 5.
In addition, we add the parts and get the total.
6 + 5 = 11 11 − 5 = 6
In subtraction, we start with the total and take away
one of the parts. What is left? The other part. 5 + 6 = 11 11 − 6 = 5

1. Write fact families.

a. b.

_____ + _____ = _______ _____ + _____ = _______

_____ + _____ = _______ _____ + _____ = _______

_______ − _____ = _____ _______ − _____ = _____

_______ − _____ = _____ _______ − _____ = _____

2. For each addition, write two subtractions using the same numbers. Start with the
TOTAL.

a. 8 + 4 = ______ b. 9 + 7 = ______ c. 7 + 6 = ______

______ – ____ = ____ ______ – ____ = ____ ______ – ____ = ____

______ – ____ = ____ ______ – ____ = ____ ______ – ____ = ____

3. For each subtraction write the matching addition.

a. 11 − 3 = ____ b. 11 − 4 = ____ c. 12 − 3 = ____

3 + ____ = 11 ____ + ____ = 11 ____ + ____ = 12

18
 When you have a subtraction problem like 15 − 9 or 16 − 8,
try to find the matching addition.

15 − 9 = ? 16 − 8 = ?
Think: 9 + ____ = 15 Think: 8 + ____ = 16
9 and how many more is 15? 8 and what number makes 16?
Guess and check! Guess and check!
Will 9 + 8 work? Or 9 + 7? Or 9 + 6? Will 8 + 5 work? Or 8 + 6? Or 8 + 7?
Or 9 + 5? You can use the trick with nine!

4. Solve each subtraction by thinking about the matching addition.

a. 14 − 8 = ____ b. 15 − 7 = ____ c. 17 − 8 = ____

8 + ____ = 14 7 + ____ = 15 8 + ____ = 17

d. 12 − 8 = ____ e. 16 − 7 = ____ f. 13 − 7 = ____

____ + ____ = 12 ____ + ____ = 16 ____ + ____ = 13

g. 13 − 8 = ____ h. 11 − 7 = ____ i. 14 − 9 = ____

____ + ____ = 13 ____ + ____ = 11 ____ + ____ = 14

5. Doubles and doubles plus one more on the night sky! Solve. Also, find the matching
additions and subtractions.

19
6. Now try to solve these subtractions by thinking of addition!

a. 12 − 8 = _____ b. 11 − 7 = _____ c. 13 − 9 = _____

d. 15 − 6 = _____ e. 18 − 9 = _____ f. 16 − 7 = _____

7. Solve.

a. Marsha had 15 crayons and Susana had 6. Marsha gave six of hers to Susana.
Now how many crayons does Marsha have?

And Susana?

Who has more? How many more?

b. Judy counted seven stars in her drawing, and she thought, “That is not enough.”
So, she drew eight more. How many stars are in her drawing now?

c. Matthew had $12. He bought a book for $7.

Now how much money does he have left?

d. John bought a toy truck for $6 and a toy backhoe for $8.
The shopkeeper said, “That makes $15.”
John said, “That is not right, it makes $13.”

Who is right?

8. Connect the problems to the right answer.

14 − 9 13 − 9 12 − 6 14 − 6
7 9
12 − 5 14 − 7 15 − 7 16 − 7
5 6
12 − 8 11 − 6 18 − 9 15 − 9
4 8
13 − 8 15 − 8 16 − 7 13 − 7

20
 Review: Completing the Next Whole Ten
1. Write the previous and next whole ten. Then, circle the ten that is nearer the given
number.

a. ______, 56, ______ b. ______, 72, ______ c. ______, 94, ______

d. ______, 37, ______ e. ______, 25, ______ f. ______, 31, ______

52 and how many more makes the next ten (60)? We can write 52 + _____ = 60.
You can solve it using a helping problem: 2 and how many more makes ten?
The answer to both problems is the same. It is 8.

2. Complete the next ten. Below, write a helping problem using numbers within 0-10.

a. 17 + _____ = 20 b. 62 + ____ = ______ c. 94 + ____ = ______

7 + _____ = 10 2 + ____ = ______ 4 + ____ = ______

3. Complete the next ten. Think of the helping problem that uses numbers within 0-10.

a. 42 + ____ = 50 b. 34 + ____ = _____ c. 66 + ____ = ______

d. 61 + ____ = _____ e. 97 + ____ = ______ f. 83 + ____ = ______

4. Circle the even numbers. 8 9 12 15 10 19 11 6 17

5. Now pick the even numbers from the previous exercise, and write each of them as a
double of some number.

a. ______ = ______ + ______ b. ______ = ______ + ______

c. ______ = ______ + ______ d. ______ = ______ + ______

21
6. Complete the next ten... and then go one more! Compare the two problems in each box.

a. 73 + _____ = 80 b. 35 + _____ = 40 c. 14 + _____ = 20

73 + _____ = 81 35 + _____ = 41 14 + _____ = 21

7. Find your way through the maze! Start at the top. You can only color a square if the sum
is a whole ten (10, 20, 30, 40, 50, 60, 70, 80, 90, or 100).

13 + 6 54 + 6 73 + 8 45 + 7 99 + 4
15 + 9 14 + 8 15 + 5 13 + 6 32 + 7
45 + 7 73 + 7 64 + 5 82 + 9 16 + 7
30 + 12 39 + 1 74 + 6 73 + 9 52 + 7
46 + 7 32 + 7 31 + 9 86 + 4 65 + 4
92 + 4 21 + 8 24 + 7 22 + 8 32 + 6
83 + 6 11 + 7 98 + 2 57 + 3 17 + 9
44 + 9 12 + 8 95 + 6 38 + 5 53 + 9
71 + 9 34 + 4 36 + 7 19 + 4 28 + 11
53 + 7 29 + 2 26 + 6 78 + 6 32 + 5

8. Complete the next whole ten. These are more challenging.

a. 17 + _____ + 1 = 20 b. 35 + _____ + 2 = 40 c. 41 + _____ + 6 = 50

12 + _____ + 4 = 20 32 + _____ + 3 = 40 44 + _____ + 3 = 50

13 + _____ + 4 = 20 36 + _____ + 3 = 40 42 + _____ + 5 = 50

9. Find as many different sums as you can to make one hundred!

90 + ____ + ____ = 100 90 + ____ + ____ = 100 90 + ____ + ____ = 100

90 + ____ + ____ = 100 90 + ____ + ____ = 100 90 + ____ + ____ = 100

90 + ____ + ____ = 100 90 + ____ + ____ = 100 90 + ____ + ____ = 100

22
 Review: Going Over Ten
Imagine that 8 wants to get some from 6 Imagine that 9 wants to get some from 7
in order to make a ten. Six gives two in order to make a ten. Seven gives one
to 8, and has only four left for itself! to 9, and has only six left for itself!

8+ 6 9+ 7
| \ | \
In the end, we In the end, we
8+2+4 9+1+6
have 10 and 4. have 10 and 6.
10 + 4 = 14 We get 14. 10 + 6 = 16 We get 16.

1. Circle all the blue balls and some of the red ones so that you get a ten. Then add
the rest.

a. 8 + 4 b. 9 + 5

10 + 2 = ______ 10 + _____ = ______

c. 8 + 6 d. 9 + 3

10 + _____ = ______ 10 + _____ = ______

e. 7 + 5 f. 9 + 8

10 + _____ = ______ 10 + _____ = ______

2. Write a number on the empty line inside the balloon so that the numbers in the balloon
make a ten. Then add the last number to 10.
a. b. c.

+ 2 = _____ + 3 = _____ + 4 = _____

d. e. f.

+ 4 = _____ + 7 = _____ + 5 = _____

23
3. Fill in. Imagine that the first number wants to become a ten.

a. 8 + 7 b. 8 + 9 c. 8 + 5
/ \ / \ / \

+ 5 + ______ + ______

10 + 5 = 15 10 + _____ = _____ 10 + _____ = _____

d. 9 + 4 e. 9 + 6 f. 9 + 9
/ \ / \ / \
+ ______ + ______ + ______

10 + _____ = _____ 10 + _____ = _____ 10 + _____ = _____

4. Add so that you get 10, 11, and 12. Notice the patterns!
a. b. c. d.

8 + ______ = 10 7 + ______ = 10 9 + ______ = 10 6 + ______ = 10

8 + ______ = 11 7 + ______ = 11 9 + ______ = 11 6 + ______ = 11

8 + ______ = 12 7 + ______ = 12 9 + ______ = 12 6 + ______ = 12

15 24 58 89 99
5. Find the even numbers.
40 51 67 100 2

6. Solve the word problems. ALSO, write an addition & subtraction sentence for them!

a. You have $8 and you buy a toy for $5 and candy for $2.
How much money do you have now?

b. Lucy had $8. Then she found $5 in her piggy

bank, and her mom gave her $2.
How much money does she have now?

c. Matthew had $8. He spent $3 on a bottle of juice.

Later he found $2 in the street.
How much money does he have now?

24
 Adding with 9
Imagine that 9 really wants to be a 10! 9 wants to be a 10! So, it takes one
It takes one from the other number from the other number (from 3).
(from 5). So, 9 becomes 10, and So, 9 becomes 10, and two dots
four dots are left over. are left over.

+ = = + = =

9 + 5 = 10 + 4 = 14 9 + 3 = 10 + 2 = 12

Use the list on the right to practice. Don't write the answers there.
Just point to different problems and say the answer aloud.
1. Circle the ten, then add.. 9+1=

9+2=

9+3=
a. 9+5 b. 9+4 c. 9+7 9+4=
10 + 4 = ____ 10 + ____ = _____ 10 + ____ = _____ 9+5=

9+6=

9+7=
d. 9 + ____ e. 9 + ____ f. 9 + ____ 9+8=
10 + ____ = _____ 10 + ____ = _____ 10 + ____ = _____ 9+9=

2. It is good to memorize the doubles, also. Fill in.

2 + 2 = _____ 5 + 5 = _____ 8 + 8 = _____

3 + 3 = _____ 6 + 6 = _____ 9 + 9 = _____

4 + 4 = _____ 7 + 7 = _____ 10 + 10 = _____

25
3. Add to nine. Think how 9 wants to be a ten, and takes 1 from the other number.

a. 9+6 b. 9+8 c. 9+5

10 + 5 = _____ 10 + _____ = _____ 10 + _____ = _____

d. 9+7 e. 9+9 f. 9+3

10 + _____ = _____ 10 + _____ = _____ 10 + _____ = _____

4. Practice the facts with nine. Do not write the answers down; just practice the sums.

9+0= 9+5= 9+9=

9+4=
9+3= 9+6= 9+1=
9 + 10 =
9+7= 9+8= 9+2=

5. Add. Remember, you can add both ways. For example, 7 + 9 is the same as 9 + 7.

a. 9 + 4 = _____ b. 9 + 7 = _____ c. 3 + 9 = _____ d. 5 + 9 = _____

8 + 9 = _____ 4 + 9 = _____ 9 + 2 = _____ 8 + 9 = _____

9 + 5 = _____ 9 + 4 = _____ 9 + 9 = _____ 9 + 6 = _____

6. What is missing?

a. 9+ = 13 b. 9+ = 16 c. + 9 = 17

9+ = 15 9+ = 14 + 9 = 11

You can use this same “trick” with 19, 29, 39, 49, and
so on. Imagine that 49 really wants to be 50, and so it
“takes” 1 from the other number. Solve.
a. 49 + 7 = _____ b. 59 + 5 = _____ c. 69 + 3 = _____

19 + 6 = _____ 89 + 9 = _____ 29 + 6 = _____

26
 Adding with 8

Imagine that 8 wants to be a 10! 8 wants to be a 10! So, it takes

It takes two from the other number two from the other number
(from 3). So, 8 becomes 10, and (from 5). So, 8 becomes 10,
only 1 is left over. and 3 are left over.

+ = = + = =

8 + 3 = 10 + 1 = 11 8 + 5 = 10 + 3 = 13

Use the list on the right to practice. Don't write the answers there.
Just point to different problems and say the answer aloud. 8+1=

1. Add. First, circle the ten. 8+2=

8+3=

8+4=
a. 8 +5 b. 8+4 c. 8 + ____
8+5=
10 + 3 = ____ 10 + ____ = ____ 10 + ____ = ____
8+6=

8+7=

d. 8 + ____ = e. 8 + ____ = f. 8 + ____ = 8+8=

10 + ____ = ____ 10 + ____ = ____ 10 + ____ = ____ 8+9=

2. It is good to memorize the doubles, also. Fill in.

2 + 2 = _____ 5 + 5 = _____ 8 + 8 = _____

3 + 3 = _____ 6 + 6 = _____ 9 + 9 = _____

4 + 4 = _____ 7 + 7 = _____ 10 + 10 = _____

27
Addition facts with eight. Do not write the answers down, but just practice the sums.

8+0= 8+5= 8+8= 8+9=

8+3= 8+7= 8+1= 8+4=

8 + 10 = 8+1= 8+6= 8+2=

3. Add and fill in what is missing.

a. 8 + 4 = _____ b. 7 + 8 = _____ c. 3 + 8 = _____

8 + 6 = _____ 8 + 5 = _____ 8 + 9 = _____

d. 8 + ____ = 13 e. 8 + ____ = 12 f. ____ + 8 = 11

8 + ____ = 15 8 + ____ = 16 ____ + 8 = 14

4. a. Jenny ate 8 strawberries, and Jack ate 5 more than what Jenny did.
How many strawberries did Jack eat?

b. Ashley is 13 years old, and Maryann is 5.

How many years older is Ashley than Maryann?

5. Find the patterns and continue them.

c.
a. 8 + 2 = _____ b. 18 + 2 = _____
1
2
of 0 is ______.
8 + 4 = _____ 18 + 4 = _____ 1
2
of 2 is ______.
8 + 6 = _____ 18 + 6 = _____ 1
2
of 4 is ______.
8 + ____ = _____ 18 + ____ = _____ 1
of _____ is ______.
2

_____ + ____ = _____ _____ + ____ = _____ 1

of _____ is ______.
2
1
_____ + ____ = _____ _____ + ____ = _____ 2
of _____ is ______.
1
_____ + ____ = _____ _____ + ____ = _____ 2
of _____ is ______.

28
 Adding with 7
We have already studied these facts: These are the new facts with 7:

7 + 8 = _____ 8 + 7 = _____ 7 + 4 = _____ 7 + 6 = _____

7 + 9 = _____ 9 + 7 = _____ 7 + 5 = _____ 7 + 7 = _____

7 + 10 = _____ 10 + 7 = _____

Tricks for remembering facts with 7

7+1=
• 7 + 7 = 14 is one of the doubles. Memorize all the doubles!
But if you forget, you can do 5 + 5 = 10, then 6 + 6 = 12, 7+2=
and then 7 + 7 = 14.
• 7 + 6 is just one more than the doubles fact 6 + 6 = 12. So, it 7+3=
is 13. Or, 7 + 6 is just one less than the doubles fact 7 + 7 = 14.
7+4=
• 7 + 4 is just one more than the ten-fact 7 + 3 = 10. So, 7 + 4 is 11.
• 7 + 5 is just one more than 7 + 4, or just one less than 7 + 6, 7+5=
so if you remember those, you can figure out 7 + 5, too.
Or maybe you have your own trick for it! 7+6=

7+7=
Use the list on the right to practice. Don't write the answers there.
Just point to different problems and say the answer aloud. 7+8=

1. Let's practice doubles—and doubles plus one more.

7+9=
Notice: the answer is also just one more!

a. 6 + 6 = _____ b. 7 + 7 = _____ c. 8 + 8 = _____

6 + 7 = _____ 7 + 8 = _____ 8 + 9 = _____

d. 9 + 9 = _____ e. 5 + 5 = _____ f. 4 + 4 = _____

9 + 10 = _____ 6 + 5 = _____ 4 + 5 = _____

29
Addition facts with seven. Do not write the answers down, but just practice the sums.

7+0= 7+5= 7+6= 7+9=

7+3= 7+9= 7+7= 7+4=

7 + 10 = 7+8= 7+1= 7+2=

2. Fill in the missing numbers.

a. 7 + 4 = _____ b. 8 + 7 = _____ c. 7 + _____ = 14 d. 7 + _____ = 12

6 + 7 = _____ 7 + 10 = _____ 7 + _____ = 13 7 + _____ = 16

7 + 5 = _____ 3 + 7 = _____ 7 + _____ = 15 7 + _____ = 11

e. 7 + 7 = _____ f. 4 + 7 = _____ g. 8 + _____ = 13 h. _____ + 7 = 17

9 + 7 = _____ 7 + 9 = _____ 8 + _____ = 16 _____ + 7 = 10

7 + 8 = _____ 3 + 7 = _____ 8 + _____ = 17 _____ + 7 = 12

3. Try these boxes! +7 +8 +9

Add 7 each time.

Add 8 each time. 4 11 3 11
Add 9 each time. 2 ____
7 ____ 6 ____ 4 ____
8 ____ 5 ____ 7 ____
10 ____ 7 ____ 8 ____
5 ____ 2 ____ 3 ____
9 ____ 4 ____ 5 ____

30
 Adding with 6

+ = + =

6 + 5 = ____ 6 + 6 = ____

This is just one more This is one of

than 5 + 5 = 10. the doubles!

Here are addition facts where we add to six. Do not write the answers down. Just go over
the problems until you remember them easily.

6+0= 6+5= 6+9=

6+6=
6+3= 6+7= 6+4=
6+8=
6 + 10 = 6+1= 6+2=

1. Fill in the missing numbers.

a. b. c. d.

6 + 4 = _____ 6 + 8 = _____ 6 + _____ = 14 _____ + 6 = 12

6 + 6 = _____ 6 + 9 = _____ 6 + _____ = 16 _____ + 6 = 15

6 + 5 = _____ 6 + 7 = _____ 6 + _____ = 12 _____ + 6 = 11

e. f. g. h.

5 + 6 = _____ 9 + 6 = _____ 7 + _____ = 14 _____ + 6 = 13

6 + 7 = _____ 8 + 6 = _____ 8 + _____ = 14 _____ + 6 = 14

4 + 6 = _____ 6 + 6 = _____ 9 + _____ = 14 _____ + 6 = 15

31
 Trick! When you add three or four numbers, first add
the numbers that make ten. It makes adding easier!
8 + 6 + 4 5 + 3 + 2 + 5

= 8 + 10 = 18 = 10 + 5 = 15

2. Add. First find the numbers that make 10. You can circle or color them. Then add the
rest. This is like hide-and-seek! Where are those numbers lurking that make ten?

a. b. c.
1 + 6 + 9 = ______ 3 + 6 + 7 + 2 = ______ 6 + 5 + 1 + 4 = ______

6 + 8 + 2 = ______ 1 + 5 + 5 + 7 = ______ 8 + 3 + 2 + 6 = ______

5 + 7 + 5 = ______ 2 + 7 + 8 + 2 = ______ 9 + 6 + 1 + 4 = ______

3. Solve the word problems.

a. There were some apples on the table. Children came in and

ate 5 apples. Later, mom saw 7 apples left on the table.
How many apples had there been at first?

b. Jeremy had $12. He bought a toy truck, and then he had $6 left.
How much did the toy truck cost?

c. Mom bought a bunch of bananas. She ate one, dad ate two, and the
children ate two. Then there were four bananas left.
How many bananas did mom buy?

d. Mike solved 9 math problems. Scott solved 5 more than Mike.

How many did Scott solve?

e. Elena solved 14 math problems and Ashley solved 7.

How many more did Elena solve than Ashley?

32
 Review—Facts with 6, 7, and 8
1. Here are the 20 addition facts with single-digit numbers where the sum is between 10
and 20. Connect the problems to the right answer.

6+6 8+6
9+9
5+8 11 5+7 15
7+9
9+5 9+2
12 16 8+7
5+6 4+7
13 17 9+8
3+9 9+4
8+8
7+7 14 6+7 18
6+9
8+3 4+8

2. Figure out the pattern and continue it.

a. b. c.

9 + ____ = 19 ____ + 16 = 17 6 + ____ = 6

8 + ____ = 18 ____ + 14 = 17 6 + ____ = 8

7 + ____ = 17 ____ + 12 = 17 6 + ____ = 10

____ + ____ = ____ ____ + ____ = ____ ____ + ____ = ____

____ + ____ = ____ ____ + ____ = ____ ____ + ____ = ____

____ + ____ = ____ ____ + ____ = ____ ____ + ____ = ____

____ + ____ = ____ ____ + ____ = ____ ____ + ____ = ____

____ + ____ = ____ ____ + ____ = ____ ____ + ____ = ____

33
3. Fill in the addition table.

+ 6 8 4 5 7 3 9

4. Solve.

a. A herd of elephants was feeding on the grass. Four of them left,

but fourteen stayed feeding. How many elephants are in the herd?

b. Sarah has five more dolls than Annie. Sarah has 10 dolls.
How many does Annie have?
Hint 1: Draw Sarah's dolls. Hint 2: Think which girl has more dolls.
Should you draw more or fewer dolls for Annie?

c. Ronnie and Luis emptied waste baskets. Ronnie emptied four more
waste baskets than Luis. Luis emptied five baskets.
How many did Ronnie empty?
Hint 1: Draw Luis's baskets. Hint 2: Think which boy emptied more of them.
Should you draw more or fewer baskets for Ronnie?

d. Cynthia ate 10 peanuts. Marie ate 7 more than Cynthia.

How many did Marie eat?

5. Add. In some problems, you can find numbers that make a ten.

a. b. c.
6 + 6 + 2 = ______ 8 + 6 + 3 = ______ 6 + 2 + 3 + 7 = ______

1 + 4 + 9 = ______ 2 + 2 + 8 = ______ 3 + 6 + 7 + 2 = ______

34
 Difference and How Many More
The difference or distance between two numbers means how far apart they are from
each other on the number line. The difference between 3 and 12 is 9, because they are
NINE steps apart.

1. Find the differences between these numbers using the number line above.

a. difference between 10 and 6: ________ b. difference between 12 and 8: ________

c. difference between 14 and 2: ________ d. difference between 17 and 6: ________

We can solve the difference between two numbers by subtracting.

What is the difference between 10 and 4? Subtract 10 – 4 = 6. The difference is 6.

2. Write a subtraction to find the difference between the numbers.

a. The difference between b. The difference between c. The difference between

10 and 4 2 and 9 8 and 3

______ – _____ = ______ ______ – _____ = ______ _____ – _____ = ______

d. The difference between e. The difference between f. The difference between

20 and 50 10 and 90 19 and 8

______ – ______ = ______ ______ – ______ = ______ _____ – ____ = ______

3. Solve the subtractions by thinking of the distance between the numbers—how far
apart they are from each other.
a. b. c. d.
20 – 16 = _____ 40 – 38 = ______ 65 – 61 = ______ 36 – 31 = ______
e. f. g. h.
100 – 99 = ______ 87 – 84 = ______ 55 – 50 = ______ 79 – 78 = ______

35
 You can also solve the difference between two numbers by thinking of addition:
how many more do you need to add to the one number to get the other?
For example, to find the difference between 12 and 7, think: 7 + ____ = 12.
(“7 and how many more makes 12?”) The answer is 5.

4. Write a “how many more” addition to find the difference between the numbers.

a. The difference between 10 and 6 b. The difference between 6 and 12

6 + ______ = 10 6 + ______ = 12
c. The difference between 15 and 8 d. The difference between 4 and 11

______ + ______ = ______ ______ + ______ = ______

5. Subtract. Think how far apart the two numbers are from each other.

+3 +____ +____
a. 15 – 12 = ____ b. 11 – 9 = ____ c. 16 – 11 = ____
12 and how many more makes 15? 9 and how many more makes 11? 11 and how many more makes 16?

There are two ways to find a difference between two numbers:

(1) Subtraction (2) A “how many more” addition
Find the difference between 100 and 2. Find the difference between 100 and 95.
It is easier to subtract 100 – 2 = 98. It is easier to think: 95 + ____ = 100.
The difference is 98. The difference is 5.

6. Find the differences.

a. The difference between 60 and 56 b. The difference between 22 and 20

c. The difference between 35 and 1 d. The difference between 67 and 3

e. The difference between 50 and 30 f. The difference between 40 and 100

36
 Whenever a word problem asks “how many more,” you can solve it in two ways.
You can either subtract, or you can write a “how many more” addition.
Either way, you are finding the difference between the two numbers.

7. Solve the word problems.

a. Jane is on page 20 and Boyd is on page 17 of the same book.

How many more pages has Jane read?

b. Mom has one dozen eggs plus five in another carton. A dozen means 12.
How many eggs does Mom have?

c. Barb is reading a 50-page book. She is on page 42.

How many more pages does she have left to read?

d. Janet worked in the garden for 2 hours in the morning and 3 hours
in the afternoon. Andy worked for 8 hours in the shop.
Who worked more hours?

How many more?

e. Betty is going batty with flies! She killed 28 flies. Her husband killed 5 flies.
How many more did she kill than him?

f. The next day, Betty was again going batty with flies. She killed 5 flies
in the living room, 12 in the kitchen, and 2 in her room.
How many flies did she kill in total?

g. Matthew had $12 and Bob had $6. Then both brothers worked helping Dad
in the garden. Matthew earned $5 and Bob earned $9.
Now, who has more money?

How much more?

37
 Number Rainbows—11 and 12
This is a number rainbow for 11. If two numbers are connected with an arc, they add up
to 11. Use the number rainbow to help you with addition and subtraction facts!

1. Practice subtraction from 11. Don't write the answers; just think them in your head.

11 – 6 = 11 – 7 = 11 – 8 = 11 – 2 =

11 – 3 = 11 – 9 = 11 – 4 = 11 – 5 =

2. Similarly, practice subtraction from 12.

12 – 5 = 12 – 7 = 12 – 10 = 12 – 6 =

12 – 9 = 12 – 4 = 12 – 3 = 12 – 8 =

38
3. Fill and color the number rainbows. Don't look at the previous page!
Then practice the subtraction problems.

11 – 4 = 11 – 2 = 11 – 3 = 11 – 9 =

11 – 8 = 11 – 5 = 11 – 6 = 11 – 7 =

12 – 8 = 12 – 3 = 12 – 4 = 12 – 9 =

12 – 6 = 12 – 10 = 12 – 7 = 12 – 5 =

For more practice, make your own number rainbows and subtractions on blank paper!

39
 Fact Families with 11
1. Fill in. In each fact family, color enough marbles to equal the first number. Then use
another color to color the rest.

Fact families with 11

10, 1, and 11 10 + 1 = _____ 11 – 10 = _____

1 + 10 = _____ 11 – 1 = _____

9, _____, and 11 9 + ____ = 11 _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

8, ____, and 11 8 + ____ = 11 _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

7, ____, and 11 7 + ____ = 11 _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

6, ____, and 11 6 + ____ = 11 _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

2. Check yourself! Can you subtract quickly without looking above?

a. 11 – 10 = _____ b. 11 – 2 = _____ c. 11 – 3 = _____

11 – 9 = _____ 11 – 4 = _____ 11 – 6 = _____

11 – 6 = _____ 11 – 5 = _____ 11 – 9 = _____

11 – 8 = _____ 11 – 7 = _____ 11 – 4 = _____

40
 Fact Families with 12
1. Fill in. In each fact family, color enough marbles to equal the first number. Then use
another color to color the rest.

Fact families with 12

10, 2, and 12 10 + 2 = _____ 12 – 10 = _____

2 + 10 = _____ 12 – 2 = _____

9, _____, and 12 9 + ____ = 12 _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

8, ____, and 12 8 + ____ = 12 _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

7, ____, and 12 ____ + ____ = _____ _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

6, ____, and 12
____ + ____ = _____ _____ – ____ = ____

2. Check yourself! Can you subtract quickly from 12 and from 11 without looking
above?
a. b. c. d.
12 – 4 = _____ 11 – 8 = _____ 12 – 6 = _____ 12 – 3 = _____

11 – 9 = _____ 12 – 7 = _____ 11 – 4 = _____ 12 – 10 = _____

12 – 8 = _____ 11 – 3 = _____ 12 – 9 = _____ 11 – 5 = _____

11 – 6 = _____ 12 – 5 = _____ 12 – 4 = _____ 11 – 7 = _____

41
3. Let's practice “how many more” additions! Remember the fact families
with 11 and 12.

a. 6 + ____ = 11 b. 7 + ____ = 12 c. ____ + 9 = 11 d. ____ + 6 = 12

8 + ____ = 11 8 + ____ = 12 ____ + 7 = 11 ____ + 9 = 12

4. Explain how you can use addition to solve a subtraction problem, such as 11 – 8.

5. Find the pattern and continue it.

a. 16 – 1 = _____ b. 0 + 17 = _____ c. 15 – 1 = _____

16 – 3 = _____ 2 + 15 = _____ 15 – 3 = _____

16 – 5 = _____ 4 + 13 = _____ 15 – 5 = _____

____ – ____ = _____ ____ + ____ = ____ ____ – ____ = _____

____ – ____ = _____ ____ + ____ = ____ ____ – ____ = _____

____ – ____ = _____ ____ + ____ = ____ ____ – ____ = _____

____ – ____ = _____ ____ + ____ = ____ ____ – ____ = _____

____ – ____ = _____ ____ + ____ = ____ ____ – ____ = _____

Imagine 14 baby blocks in three stacks. One stack has 6 and

the third stack has 4. How many are in the middle stack?
We can write an addition where one number is missing: 6 + ____ + 4 = 14.
Figure out a way to solve this problem! Then solve the rest of the problems below.

a. 6 + ____ + 4 = 14 b. 2 + ____ + 2 = 8 c. 10 + ____ + 4 = 17

8 + ____ + 3 = 13 3 + ____ + 3 = 9 10 + ____ + 2 = 15

See also the game http://www.carstensstudios.com/mathdoodles/sumsstacker.html

42
 Number Rainbows—13 and 14
1. Fill in and color the number rainbows. Then practice the subtractions.

13 – 7 = 13 – 4 = 13 – 9 = 13 – 10 =

13 – 5 = 13 – 6 = 13 – 11 = 13 – 8 =

14 – 8 = 14 – 3 = 14 – 7 = 14 – 6 =

14 – 5 = 14 – 9 = 14 – 11 = 14 – 4 =

For more practice, make your own number rainbows and subtractions on blank paper!

43
 Fact Families - 13 and 14
1. Fill in. In each fact family, color the marbles so they match the numbers in it.

Fact families with 13

10, 3, and 13 10 + 3 = _____ 13 – 10 = _____

3 + 10 = _____ 13 – 3 = _____

9, _____, and 13 9 + ____ = 13 _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

8, ____, and 13 8 + ____ = 13 _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

7, ____, and 13 7 + ____ = 13 _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

2. Connect with a line the problems that are from the same fact family. You don't need to
write the answers.

13 – 7 = 11 – 4 = 12 – 7 =

5+ = 12 11 – 8 = 13 – 6 =

11 – 3 = 5+ = 13 3+ = 12

8+ = 13 12 – 5 = 13 – 5 =

12 – 3 = 6+ = 13 3+ = 11

7+ = 11 9+ = 12 4+ = 11

44
3. Fill in. In each fact family, color the marbles so they match the numbers in it.

Fact families with 14

10, 4, and 14 10 + 4 = _____ 14 – 10 = _____

4 + 10 = _____ 14 – 4 = _____

9, _____, and 14 9 + ____ = 14 _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

8, ____, and 14 8 + ____ = 14 _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

7, ____, and 14 7 + ____ = 14 _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

4. Subtract.

a. 13 – 8 = ____ b. 13 – 5 = ____ c. 12 – 7 = ____ d. 12 – 9 = ____

14 – 6 = ____ 13 – 4 = ____ 13 – 7 = ____ 14 – 9 = ____

5. Find the missing numbers.

a. 9+ = 14 b. 6+ = 14 c. 6+ = 12

d. –9=4 e. –7=7 f. –9=3

g. 14 – =8 h. 12 – =7 i. 13 – =8

45
6. Solve the word problems.

a. Ted arranged his toy cars in rows. The first row had
seven cars, the second had seven, and the third row
had four. How many cars does Ted have?

b. If you have 14 strawberries and I have eight,

how many more do you have?

c. Dad has six cherries and Mom has five more than him.
How many cherries does Mom have?

d. At first Mom had 20 apples to make a pie,

but she gave each of the four children one apple
before she made the pie. How many apples
did she have left for the pie?

7. Figure out the patterns and continue them!

+ + + + + + + +
a.

40 48 56 64 72 _____ _____ _____ _____

+ + + + + + + +
b.

17 21 25 29 _____ _____ _____ _____ _____

46
 Fact Families with 15
1. Fill in. In each fact family, color the marbles so they match the numbers in it.

Fact families with 15

10, 5, and 15 10 + 5 = _____ 15 – 10 = _____

5 + 10 = _____ 15 – 5 = _____

9, _____, and 15 9 + ____ = 15 _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

8, ____, and 15 8 + ____ = 15 _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

2. Subtract.

a. 15 – 5 = ______ b. 15 – 8 = ______ c. 15 – 4 = ______

d. 15 – 9 = ______ e. 15 – 6 = ______ f. 15 – 7 = ______

3. Alice does not remember the answer to 15 – 9.

Explain how she can solve it using addition.

4. Count by threes.
+ 3 + 3 + 3 + 3 + 3 + 3 + 3 + 3

9 33

47
5. These word problems all have to do with “more.” Draw a picture of how many things
the one person has in the problem. Then think carefully who has more. Will you need
to draw more or fewer things for the other person in the problem?

a. Michelle has 7 peaches and Jacob has three more than her.
How many does Jacob have?

b. William has three more books than Ethan. William has 11 books.
How many does Ethan have?

c. Noah picked 15 pine cones and Aiden picked 9.

How many more did Noah pick than Aiden?

d. Emma picked 5 more pine cones than Sophia.

If Emma picked 15, how many did Sophia pick?

6. Write each number as a double of some other number.

a. 6 = ____ + ____ b. 12 = ____ + ____ c. 10 = ____ + ____

d. 18 = ____ + ____ e. 20 = ____ + ____ f. 8 = ____ + ____

7. Judy picked 7 tomatoes from the garden, and John picked 9.

Then they gave half of their tomatoes to a neighbor.
How many did they keep?

8. Write or say all the even numbers from 0 to 20.

9. Find how much the things cost together.

a. bike, $28, and kite, $30 b. jeans, $47, and shoes, $30, and toy, $10

together $ _________ together $ _________

48
 Fact Families with 16
1. Fill in. Color the marbles, using two colors, so that the coloring matches the numbers.

Fact families with 16

10, 6, and 16 10 + 6 = _____ 16 – 10 = _____

6 + 10 = _____ 16 – 6 = _____

9, _____, and 16 9 + ____ = 16 _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

8, ____, and 16 8 + ____ = 16 _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

2. Subtract.
a. b. c. d.
15 – 10 = _____ 13 – 9 = _____ 14 – 8 = _____ 15 – 7 = _____

13 – 10 = _____ 16 – 9 = _____ 13 – 8 = _____ 16 – 7 = _____

16 – 10 = _____ 14 – 9 = _____ 16 – 8 = _____ 13 – 7 = _____

3. Connect the problems to the answer with a line.

15 – 9 3 17 – 10 7 17 – 9

14 – 9 4 16 – 9 8 16 – 6

14 – 10 5 16 – 10 9 18 – 10

13 – 9 6 18 – 9 10 19 – 9

49
4. Figure out the patterns and continue them!

+ + + + + + + +
a.

6 9 12 15 ____ ____ ____ ____ ____

+ + + + + + +
+
b.

12 16 20 24 ____ ____ ____ ____ ____

5. Solve the word problems.

a. A class has 24 children. Two of them were sick one day and two had to
leave to go to the dentist. How many children were in class that day?

b. If you have $10, and Mom gives you $4 more,

can you buy a book for $13?

c. You had $20 and you bought sandals for

$17. How many dollars do you have left?

d. Erika has saved $12. She wants to buy a gift that

costs $16. How much more money does she need?

e. Five boys came to play ball. Then, seven girls came. Then, one girl
had to go home. Are there now more boys or girls playing ball?

How many more?

6. Compare and write < , > , or = .

a. 35 20 + 5 b. 23 + 5 23 + 6 c. 16 – 8 15 – 8

d. 15 6+7 e. 31 + 4 31 + 3 f. 15 – 9 16 – 9
50
 Fact Families - 17 and 18
1. Fill in. Color the marbles, using two colors, so that the coloring matches the numbers.

Fact families with 17

10, 7, and 17 10 + 7 = _____ 17 – 10 = _____

____ + ____ = _____ _____ – ____ = ____

9, _____, and 17 9 + ____ = 17 _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

Fact families with 18

10, 8, and 18 10 + 8 = _____ 18 – 10 = _____

____ + ____ = _____ _____ – ____ = ____

9, _____, and 18 9 + ____ = 18 _____ – ____ = ____

____ + ____ = _____ _____ – ____ = ____

2. Subtract, practicing the basic facts. Remember to think of fact families.

a. b. c. d.
17 – 10 = _____ 15 – 9 = _____ 14 – 6 = _____ 12 – 9 = _____

17 – 9 = _____ 15 – 8 = _____ 14 – 7 = _____ 12 – 8 = _____

18 – 10 = _____ 16 – 9 = _____ 13 – 6 = _____ 11 – 9 = _____

18 – 9 = _____ 16 – 8 = _____ 13 – 7 = _____ 11 – 8 = _____

51
3. Write < , > , or = . Can you compare these without calculating?

1
a. 45 + 8 45 + 5 b. 50 – 6 50 – 8 c. of 12 12
2

1 1 1
d. of 16 of 14 e. 27 – 6 27 – 3 f. of 20 10
2 2 2

4. Fill in the missing numbers.

a. 14 – 8 = b. 16 – 8 = c. 17 – 8 =

d. –9=6 e. –8=7 f. –4=8

g. 17 – =9 h. 18 – =9 i. 15 – =6

5. Solve the word problems.

a. A baby slept four hours and woke up to nurse. Then she slept
another two hours and woke up to nurse. Then she slept three hours
more and nursed again. Then she slept three hours until the morning.

How many hours did the baby sleep?

b. Mom needs 16 eggs to make cakes. The store sells eggs in cartons of 12.
How many cartons does she need to buy?

How many eggs will she have left over?

6. Find the missing numbers. You can also work backwards, starting from 70!

–10 –1 –5 –4 –2 –8

100 ______ ______ ______ ______ ______ 70

52
 Review
1. Here are the 20 addition facts with single-digit numbers where the sum is between 10
and 20. Connect the problems to the right answer.

5+6 4+8
6+9
6+8 11 6+7 15
8+8
6+6 9+4
12 16 7+8
4+7 7+7
13 17 9+8
3+9 2+9
7+9
3+8 14 5+7 18
9+9
8+5 5+9

2. Connect with a line the problems that are from the same fact family. You don't need
to write the answers.

13 – 7 = 12 – 5 = 15 – 7 =

7+ = 15 11 – 8 = 13 – 6 =

11 – 3 = 9+ = 17 5+ = 14

8+ = 17 15 – 8 = 17 – 8 =

14 – 5 = 6+ = 13 3+ = 11

7+ = 12 9+ = 14 + 5 = 12

3. Find the differences.

a. The difference of 80 and 87 ________ b. The difference of 45 and 2 ________

c. The difference of 15 and 8 ________ d. The difference of 13 and 4 ________

53
4. Find the missing numbers.

a. 8+ = 15 b. 7+ = 14 c. 6+ = 13

d. 13 − =5 e. 14 − =8 f. 15 − =9

g. 11 − 6 = h. 12 − 7 = i. 12 − 4 =

5. Find the missing steps.

–5 –5 –2 –3 –6 –3

75 ______ ______ ______ ______ ______ 51

6. a. You have an odd number of cookies and so does your friend. You put your cookies
together and share them. Can you share them evenly or not?
Cookies Cookies your Together Can you
even/odd
you have friend has we have share evenly?

3 5
5 9
9 3
9 7

b. You have an odd number of cookies and your friend has an even number of cookies.
You put your cookies together and share them. Can you share them evenly or not?
Cookies Cookies your Together Can you
even/odd
you have friend has we have share evenly?

5 6
7 8
9 4
1 12

54
7. Solve the puzzle. What happened to the teddy bear in the desert?

5+9 7+8 13 – 8 2 + 9 10 + 5 9+7 4+7 9+6

____ ____ ____ ____ ____ ____ ____ ____

7 + 7 13 – 6 19 – 4 11 + 5 13 – 7 3 + 13 11 – 5 13 – 4 6+9

____ ____ ____ ____ ____ ____ ____ ____ ____

A E I O G H T W N
Key:
9 6 14 11 5 16 15 8 7

8. Solve the word problems.

a. Jack has 13 tennis balls and Jane has 20.

How many more does Jane have than Jack?

b. Emma has three more flowers than Sofia. If Emma

has 14 flowers, how many does Sofia have?

c. In a chess game, Jacob has 2 more pawns than Anna.

If Anna has five pawns, how many does Jacob have?

d. You have $20, and you want to buy a Lego set that costs $28.
How many dollars do you still need to save?

Later, a neighbor pays you $2 for helping rake leaves.

How much more money do you need after that?

e. In a board game, you need to move 18 more squares to get to the end
of the game. You roll 6 and 5 on two dice and move that many squares.
Now how many more squares are there to the end?

What kind of numbers on the two dice would get you to the end?

55
56
 Math Mammoth Add & Subtract 2-A
Answer Key
Add Using “Just One More”, p. 7
1.

a. 8 + 2 = 10 b. 4 + 6 = 10 c. 7 + 3 = 10
8 + 3 = 11 4 + 7 = 11 8 + 3 = 11
d. 1 + 9 = 10 e. 5 + 5 = 10 f. 4 + 4 = 8
2 + 9 = 11 5 + 6 = 11 5+ 4 =9

2. a. 3, 4 b. 2, 3 c. 4, 5 d. 6 e. 2 f. 8
3.

a. b. c. d.
7+2=9 5 + 6 = 11 4 + 6 = 10 2 + 9 = 11
3 + 8 = 11 3+4=7 2 + 8 = 10 5+4=9
5 + 5 = 10 6 + 4 = 10 7 + 4 = 11 3 + 7 = 10

4. a. 13 b. 14 c. 17 d. 16 e. 11 f. 19 g. 15 h. 18 i. 11 j. 17 k. 13 1. 15
5. a. Joe gave away ten balloons. Joe still has two balloons.
b. Marsha found thirteen shirts.
c. She had to wash ten shirts.
d. There were three more girls.
e. There were just enough shirts for everyone.

A “Trick” with Nine and Eight, p. 9

1.

a. 9 + 6 b. 9 + 4

10 + 5 = 15 10 + 3 = 13

c. 9 + 3 d. 9 + 5

10 + 2 = 12 10 + 4 = 14

2.

a. 9 + 8 b. 9 + 7 c. 9 + 9
/ \ / \ / \
9+ 1 +7 9+ 1 +6 9+ 1 +8
10 + 7 = 17 10 + 6 = 16 10 + 8 = 18

57
3.

a. 8 + 6 b. 8 + 7

10 + 4 = 14 10 + 5 = 15
c. 8 + 3 d. 8 + 4

10 + 1 = 11 10 + 2 = 12

4.

a. 8 + 8 b. 8 + 5 c. 8 + 7
/ \ / \ / \
8+ 2 +6 8+ 2 +3 8+ 2 +5
10 + 6 = 16 10 + 3 = 13 10 + 5 = 15

5. a. Not correct. 6 + 6 = 12 d. Not correct. 9 + 7 = 16

6. a. There are six apples left. b. Jeremy has 15 apples.
c. Jeremy picked two more flowers. Together, they have 16 flowers.
d. The train of cars was 14 cm long.
7.

a. b. c.
7 + 3 + 5 = 15 9 + 1 + 2 = 12 7 + 3 + 5 = 15
d. e. f.
6 + 4 + 6 = 16 8 + 2 + 4 = 14 5 + 5 + 8 = 18

8. a. 14 b. 15 c. 13 d. 12 e. 15 f. 18 g. 14 h. 16 i. 11
Puzzle corner: a. 8 b. 6 c. 4

Adding Within 20, p. 12

1.

a. 5 + 5 = 10 b. 6 + 6 = 12 c. 7 + 7 = 14
5 + 6 = 11 and 6 + 7 = 13 and 7 + 8 = 15 and
6 + 5 = 11 7 + 6 = 13 8 + 7 = 15
d. 8 + 8 = 16 e. 9 + 9 = 18 f. 10 + 10 = 20
8 + 9 = 17 and 9 + 10 = 19 and 10 + 11 = 21 and
9 + 8 = 17 10 + 9 = 19 11 + 10 = 21

2. a. 17 b. 12 c. 14 d. 15
3.

a. 1 + 9 = 10 b. 3 + 7 = 10 c. 8 + 2 = 10
1 + 10 = 11 or 3 + 8 = 11 or 8 + 3 = 11 or
2 + 9 = 11 4 + 7 = 11 9 + 2 = 11
d. 6 + 4 = 10 e. 5 + 5 = 10 f. 7 + 3 = 10
6 + 5 = 11 or 5 + 6 = 11 or 7 + 4 = 11 or
7 + 4 = 11 6 + 5 = 11 8 + 3 = 11

58
4. a. 7 + 7 = 14 Doubles chart
b. 9 + 7 = 16 Trick with nine
c. 8 + 3 = 11 Trick with eight
d. 6 + 7 = 13 Just one more than a double
e. 5 + 6 = 11 “Just one more” than a sum with 10
f. 5 + 8 = 13 Trick with eight
g. 8 + 8 = 16 Doubles chart
h. 4 + 9 = 13 Trick with nine
5. a. 9 + 5 − 2 = $12 Maria has twelve dollars.
b. 9 + 3 = 12; 8 + 3 = 11 Ashley has one more shirt.
c. 10 − 6 − 1 = 3 Emily has three dollars.
d. 8 − 2 + 4 = 10 They have 10 tennis balls.
6.

a. 8 + 2 = 10 b. 5 + 3 = 8 c. 9 + 2 = 11 d. 7 + 3 = 10
8 + 4 = 12 5 + 5 = 10 9 + 4 = 13 7 + 5 = 12
8 + 6 = 14 5 + 7 = 12 9 + 6 = 15 7 + 7 = 14
8 + 8 = 16 5 + 9 = 14 9 + 8 = 17 7 + 9 = 16

7.

15 10 13 14 7
+8 −3 −2 −2 +5 −3 +4 −4 −3 +9
7 12 8 10 10 16

8. a. 18, 28, 38, 48, 58, 68, 78, 88, 98

b. 27, 37, 47, 57, 67, 77, 87, 97, 107
9.
a. 6 + 6 = 12 b. 8 + 8 = 16 c. 6 + 5 = 11
6 + 7 = 13 9 + 7 = 16 7 + 4 = 11

10. 9 + 6 = 15 cm Check the student’s lines.

11.
a. b. c. d.
8 + 8 = 16 7 + 8 = 15 7 + 7 = 14 5 + 8 = 13
2 + 9 = 11 9 + 6 = 15 9 + 8 = 17 3 + 9 = 12
7 + 5 = 12 6 + 5 = 11 7 + 4 = 11 7 + 6 = 13
e. f. g. h.
9 + 4 = 13 8 + 6 = 14 9 + 2 = 11 6 + 9 = 15
4 + 8 = 12 6 + 6 = 12 8 + 5 = 13 8 + 7 = 15
6 + 7 = 13 5 + 9 = 14 5 + 7 = 12 8 + 4 = 12
i. j. k. l.
9 + 3 = 12 4 + 9 = 13 9 + 9 = 18 8 + 9 = 17
4 + 7 = 11 7 + 7 = 14 6 + 8 = 14 5 + 6 = 11
9 + 5 = 14 3 + 8 = 11 6 + 6 = 12 8 + 3 = 11

Puzzle corner: 7 + 6 = 13 8 + 8 = 16
+ + + +
8 + 3 = 11 6 + 9 = 15
= = = =
15 9 14 17

59
Subtract to Ten, p. 16
1. b. 14 − 4 = 10 c. 16 − 6 = 10 d. 15 − 5 = 10
2. a. 13 − 3 = 10 b. 17 − 7 = 10 c. 19 − 9 = 10
3.
a. 14 − 7 b. 15 − 8 c. 16 − 8
/ \ / \ / \
14 − 4 − 3 15 − 5 − 3 16 − 6 − 2

10 − 3 = 7 10 − 3 = 7 10 − 2 = 8
d. 13 − 6 e. 12 − 6 f. 13 − 4
/ \ / \ / \
13 − 3 − 3 12 − 2 − 4 13 − 3 − 1

10 − 3 = 7 10 − 4 = 6 10 − 1 = 9

4.
a. 12 − 6 b. 15 − 9 c. 13 − 8
/ \ / \ / \
12 − 2 − 4 = 6 15 − 5 − 4 = 6 13 − 3 − 5 = 5
d. 13 − 7 e. 14 − 7 f. 12 − 4
/ \ / \ / \
13 − 3 − 4 = 6 14 − 4 − 3 = 7 12 − 2 − 2 = 8

5. a. 7 b. 8 c. 7 d. 8 e. 7 f. 9 g. 8 h. 5
6. a. 13 − 8 = 5 Tom is five years older than Juan.
b. 13 − 9 = 4 Tom is four years older than Alice.
c. 15 − 10 = 5 Tom is still five years older than Juan.
7.
11 5 16 13 12
+5 −4 −2 +9 +2 −8 +5 −6 +5 −2
6 7 14 8 7 10

60
Using Addition to Subtract, p. 18
1.

a. b.

8 + 5 = 13 5 + 8 = 13 9 + 7 = 16 7 + 9 = 16
13 − 8 = 5 13 − 5 = 8 16 − 9 = 7 16 − 7 = 9

2.
a. 8 + 4 = 12 b. 9 + 7 = 16 c. 7 + 6 = 13
12 – 8 = 4 16 – 9 = 7 13 – 7 = 6
12 – 4 = 8 16 – 7 = 9 13 – 6 = 7

3.
a. 11 − 3 = 8 b. 11 − 4 = 7 c. 12 − 3 = 9
3 + 8 = 11 4 + 7 = 11 3 + 9 = 12

4.
a. 14 − 8 = 6 b. 15 − 7 = 8 c. 17 − 8 = 9
8 + 6 = 14 7 + 8 = 15 8 + 9 = 17
d. 12 − 8 = 4 e. 16 − 7 = 9 f. 13 − 7 = 6
8 + 4 = 12 7 + 9 = 16 7 + 6 = 13
g. 13 − 8 = 5 h. 11 − 7 = 4 i. 14 − 9 = 5
8 + 5 = 13 7 + 4 = 11 9 + 5 = 14

5.

The matching additions and subtractions are:

8 + 8 = 16 and 16 − 8 = 8
7 + 8 = 15 and 15 − 7 = 8
8 + 9 = 17 and 17 − 8 = 9
7 + 7 = 14 and 14 − 7 = 7
6.
a. 12 − 8 = 4 b. 11 − 7 = 4 c. 13 − 9 = 4
d. 15 − 6 = 9 e. 18 − 9 = 9 f. 16 − 7 = 9

7. a. 15 − 6 = 9 Marsha has nine crayons.

6 + 6 = 12 Susana has 12 crayons now.
Susana has more crayons.
Susana has three more crayons.
b. 7 + 8 = 15. She has 15 stars in her drawing.
c. 12 − 7 = 5 Matthew has $5.
d. 6 + 8 = 14 Neither are right. The total is 14.

61
8.

Review: Completing the Next Whole Ten, p. 21

1. a. 50, 56, 60; d. 30, 37, 40 6. a. 7, 8 b. 5, 6 c. 6, 7

b. 70, 72, 80; e. 20, 25, 30; middle of both
c. 90, 94, 100; f. 30, 31, 40 7.

2. a. 3, 3 b. 62 + 8 = 70, 2 + 8 = 10
c. 94 + 6 = 100, 4 + 6 = 10
3. a. 42 + 8 = 50 b. 34 + 6 = 40 c. 66 + 4 = 70
d. 61 + 9 = 70 e. 97 + 3 = 100 f. 83 + 7 = 90
4. The even numbers are 8, 12, 10, and 6.
5.
8. a. 2, 4, 3 b. 3, 5, 1 c. 3, 3, 3
a. 8 = 4 + 4 b. 12 = 6 + 6
9. Answers will vary. For example:
c. 10 = 5 + 5 d. 6 = 3 + 3 90 + 9 + 1 = 100; 90 + 8 + 2 = 100; 90 + 7 + 3 = 100;
90 + 6 + 4 = 100; 90 + 5 + 5 = 100; 90 + 4 + 6 = 100;
90 + 3 + 7 = 100; 90 + 2 + 8 = 100; 90 + 1 + 9 = 100

Review: Going Over Ten, p. 23

1.

a. 8 + 4 = 10 + 2 = 12 b. 9 + 5 = 10 + 4 = 14

c. 8 + 6 = 10 + 4 = 14 d. 9 + 3 = 10 + 2 = 12

e. 7 + 5 = 10 + 2 = 12 f. 9 + 8 = 10 + 7 = 17

2. a. ( 7 + 3 ) + 2 = 12 b. ( 5 + 5 ) + 3 = 13 c. ( 8 + 2 ) + 4 = 14
d. ( 6 + 4 ) + 4 = 14 e. ( 9 + 1 ) + 7 = 17 f. ( 7 + 3 ) + 5 = 15

3.
a. 8 + 7 b. 8 + 9 c. 8 + 5
/ \ / \ / \
8+ 2 + 5 8+ 2 + 7 8+ 2 + 3
10 + 5 = 15 10 + 7 = 17 10 + 3 = 13

d. 9 + 4 e. 9 + 6 f. 9 + 9
/ \ / \ / \
9+ 1 + 3 9+ 1 + 5 9+ 1 + 8
10 + 3 = 13 10 + 5 = 15 10 + 8 = 18

62
4. a. 2, 3, 4 b. 3, 4, 5 c. 1, 2, 3 d. 4, 5, 6
5. The even numbers are 24, 58, 40, 100, and 2.
6. a. You have $1 left. $8 − $5 − $2 = $1 b. She has $15. $8 + $5 + $2 = $15 c. Now, he has $7. $8 − $3 + $2 = $7

Adding with 9, p. 25
1. a. 14, 14 b. 9 + 4 = 13; 10 + 3 = 13 c. 9 + 7 = 16; 10 + 6 = 16
d. 9 + 6 = 15; 10 + 5 = 15 e. 9 + 8 = 17; 10 + 7 = 17 f. 9 + 9 = 18; 10 + 8 = 18
2. 4, 6, 8 10, 12, 14 16, 18, 20
3. a. 15, 15 b. 17, 10 + 7 = 17 c. 14, 10 + 4 = 14
d. 16, 10 + 6 = 16 e. 18, 10 + 8 = 18 f. 12, 10 + 2 = 12
4.

9 + 0 = 9 9 + 5 = 14 9 + 9 = 18
9 + 4 = 13
9 + 3 = 12 9 + 6 = 15 9 + 1 = 10
9 + 10 = 19
9 + 7 = 16 9 + 8 = 17 9 + 2 = 11

5. a. 13, 17, 14 b. 16, 13, 13 c. 12, 11, 18 d. 14, 17, 15

6. a. 4, 6 b. 7, 5 c. 8, 2
Puzzle corner. a. 56, 25 b. 64, 98 c. 72, 35

Adding with 8, p. 27
1. a. 13 b. 10 + 2 = 12 c. 8 + 7; 10 + 5 = 15 d. 8 + 6; 10 + 4 = 14 e. 8 + 8; 10 + 6 = 16 f. 8 + 3; 10 + 1 = 11
2. 4, 6, 8 10, 12, 14 16, 18, 20

8+0= 8 8 + 5 = 13 8 + 8 = 16 8 + 9 = 17
8 + 3 = 11 8 + 7 = 15 8 + 1 = 9 8 + 4 = 12
8 + 10 = 18 8 + 1 = 9 8 + 6 = 14 8 + 2 = 10

3. a. 12, 14 b. 15, 13 c. 11, 17 d. 5, 7 e. 4, 8 f. 3, 6

4. a. Jack ate 13. 8 + 5 = 13 b. Eight years older. 13 − 5 = 8 or 5 + 8 = 13

5. a. b. c.
1
8 + 2 = 10 18 + 2 = 20 of 0 is 0.
2
1
8 + 4 = 12 18 + 4 = 22 of 2 is 1.
2
1
8 + 6 = 14 18 + 6 = 24 of 4 is 2.
2
1
8 + 8 = 16 18 + 8 = 26 of 6 is 3.
2
1
8 + 10 = 18 18 + 10 = 28 of 8 is 4.
2
1
8 + 12 = 20 18 + 12 = 30 of 10 is 5.
2
1
of 12 is 6.
8 + 14 = 22 18 + 14 = 32 2

63
Adding with 7, p. 29

We have already studied these addition facts: These are the new facts with 7:

7 + 8 = 15 8 + 7 = 15
7 + 4 = 11 7 + 6 = 13
7 + 9 = 16 9 + 7 = 16
7 + 5 = 12 7 + 7 = 14
7 + 10 = 17 10 + 7 = 17

1. a. 12; 13 b. 14; 15 c. 16; 17 d. 18; 19 e. 10; 11 f. 8; 9

7 + 0 = 7 7 + 5 = 12 7 + 6 = 13 7 + 9 = 16
7 + 3 = 10 7 + 9 = 16 7 + 7 = 14 7 + 4 = 11
7 + 10 = 17 7 + 8 = 15 7 + 1 = 8 7 + 2 = 9

2. a. 11, 13, 12 b. 15, 17, 10 c. 7, 6, 8 d. 5, 9, 4 e. 14, 16, 15 f. 11, 16, 10 g. 5, 8, 9 h. 10, 3, 5

3. +7 +8 +9

4 11 3 11 2 11
7 14 6 14 4 13
8 15 5 13 7 16
10 17 7 15 8 17
5 12 2 10 3 12
9 16 4 12 5 14

Adding with 6, p. 31

6 + 5 = 11 6 + 6 = 12

6 + 0 = 6 6 + 5 = 11 6 + 9 = 15
6 + 6 = 12
6 + 3 = 9 6 + 7 = 13 6 + 4 = 10
6 + 8 = 14
6 + 10 = 16 6 + 1 = 7 6 + 2 = 8

1. a. 10, 12, 11 b. 14, 15, 13 c. 8, 10, 6 d. 6, 9, 5 e. 11, 13, 10 f. 15, 14, 12 g. 7, 6, 5 h. 7, 8, 9

2.

a. b. c.
1 + 6 + 9 = 16 3 + 6 + 7 + 2 = 18 6 + 5 + 1 + 4 = 16
6 + 8 + 2 = 16 1 + 5 + 5 + 7 = 18 8 + 3 + 2 + 6 = 19
5 + 7 + 5 = 17 2 + 7 + 8 + 2 = 19 9 + 6 + 1 + 4 = 20

3. a. 12 apples. 7 + 5 = 12 b. It cost $6. $6 + $6 = 12 or $12 − $6 = $6 c. Nine bananas. 4 + 1 + 2 + 2 = 9

d. He solved 14 problems. 9 + 5 = 14 e. She solved 7 more problems than Ashley. 14 − 7 = 7 or 7 + 7 = 14

64
Review - Facts with 6, 7, and 8, p. 33
1.

2.

a. b. c.
9 + 10 = 19 1 + 16 = 17 6 + 0 = 6
8 + 10 = 18 3 + 14 = 17 6 + 2 = 8
7 + 10 = 17 5 + 12 = 17 6 + 4 = 10
6 + 10 = 16 7 + 10 = 17 6 + 6 = 12
5 + 10 = 15 9 + 8 = 17 6 + 8 = 14
4 + 10 = 14 11 + 6 = 17 6 + 10 = 16
3 + 10 = 13 13 + 4 = 17 6 + 12 = 18
2 + 10 = 12 15 + 2 = 17 6 + 14 = 20
1 + 10 = 11 17 + 0 = 17 6 + 16 = 22

3.
+ 6 8 4 5 7 3 9
7 13 15 11 12 14 10 16
9 15 17 13 14 16 12 18
5 11 13 9 10 12 8 14

4. a. 18 elephants. 4 + 14 = 18 b. Annie has five dolls. 10 − 5 = 5.

c. He emptied 9 baskets. 5 + 4 = 9. d. She ate 17. 10 + 7 = 17
5. a. 14, 14 b. 17, 12 c. 18, 18

65
Difference and How Many More, p. 35
1. a. 4 b. 4 c. 12 d. 11
2.
The difference between 10 and 4 The difference between 2 and 9 The difference between 8 and 3
a. 10 – 4 = 6 b. 9 – 2 = 7 c. 8 – 3 = 5
The difference between 20 and 50 The difference between 10 and 90 The difference between 19 and 8
d. 50 – 20 = 30 e. 90 – 10 = 80 f. 19 – 8 = 11

3. a. 4 b. 2 c. 4 d. 5 e. 1 f. 3 g. 5 h. 1
4.

a. The difference between 10 and 6 is 4 . b. The difference between 6 and 12 is 6 .

6 + 4 = 10 6 + 6 = 12
c. The difference between 15 and 8 is 7 . d. The difference between 4 and 11 is 7 .
8 + 7 = 15 4 + 7 = 11

5. a. 3 b. 2 c. 5
6. a. 4 b. 2 c. 34 d. 64 e. 20 f. 60
7. a. Jen has read three more pages. 20 − 17 = 3 or 17 + 3 = 20
b. Mom has 17 eggs. 12 + 5 = 17
c. She has eight pages left. 42 + 8 = 50 or 50 − 42 = 8
d. Andy worked more hours. He worked three hours more. Janet worked: 2 + 3 = 5 hours. The difference: 8 − 5 = 3.
e. She killed 23 more flies than her husband. 28 − 5 = 23
f. She killed 19 flies. 5 + 12 + 2 = 19
g. Matthew has more. He has $2 more. Matthew has: $12 + $5 = $17. Bob has $6 + $9 = $15.

Number Rainbows - 11 and 12, p. 38

The student is supposed to practice mentally and not write the answers down. The answers are of course easily seen from
the rainbow. Encourage the child to also practice the subtraction problems while keeping the rainbow covered. There is a
page for number rainbows with 13 and 14 also (a little later). Feel free to also draw or have the child draw (better!) ones for
15, 16, 17, and 18.

Fact Families with 11, p. 40

1.

Fact families with 11

10, 1, and 11
10 + 1 = 11 11 – 10 = 1
1 + 10 = 11 11 – 1 = 10

9, 2, and 11
9 + 2 = 11 11 – 2 = 9
2 + 9 = 11 11 – 9 = 2

8, 3, and 11
8 + 3 = 11 11 – 8 = 3
3 + 8 = 11 11 – 3 = 8

7, 4, and 11
7 + 4 = 11 11 – 4 = 7
4 + 7 = 11 11 – 7 = 4

6, 5, and 11
6 + 5 = 11 11 – 6 = 5
5 + 6 = 11 11 – 5 = 6

66
2.

a. 11 – 10 =1 b. 11 – 2 = 9 c. 11 – 3 = 8
11 – 9 = 2 11 – 4 = 7 11 – 6 = 5
11 – 6 = 5 11 – 5 = 6 11 – 9 = 2
11 – 8 = 3 11 – 7 = 4 11 – 4 = 7

Fact Families with 12, p. 41

1.

Fact families with 12

10, 2, and 12 10 + 2 = 12 12 – 10 = 2
2 + 10 = 12 12 – 2 = 10

9, 3, and 12 9 + 3 = 12 12 – 9 = 3
3 + 9 = 12 12 – 3 = 9

8, 4, and 12 8 + 4 = 12 12 – 8 = 4
4 + 8 = 12 12 – 4 = 8

7, 5, and 12 7 + 5 = 12 12 – 7 = 5
5 + 7 = 12 12 – 5 = 7

6, 6, and 12
6 + 6 = 12 12 – 6 = 6

2.
a. b. c. d.
12 – 4 = 8 11 – 8 = 3 12 – 6 = 6 12 – 3 = 9
11 – 9 = 2 12 – 7 = 5 11 – 4 = 7 12 – 10 = 2
12 – 8 = 4 11 – 3 = 8 12 – 9 = 3 11 – 5 = 6
11 – 6 = 5 12 – 5 = 7 12 – 4 = 8 11 – 7 = 4

3. a. 5, 3 b. 5, 4 c. 2, 4 d. 6, 3
4. Answers will vary. For example: Think of the addition 8 + ___ = 11.
The number that is missing is 3 and that is the answer to 11 – 8.
5.
a. b. c.
16 – 1 = 15 0 + 17 = 17 15 – 1 = 14
16 – 3 = 13 2 + 15 = 17 15 – 3 = 12
16 – 5 = 11 4 + 13 = 17 15 – 5 = 10
16 – 7 = 9 6 + 11 = 17 15 – 7 = 8
16 – 9 = 7 8 + 9 = 17 15 – 9 = 6
16 – 11 = 5 10 + 7 = 17 15 – 11 = 4
16 – 13 = 3 12 + 5 = 17 15 – 13 = 2
16 – 15 = 1 14 + 3 = 17 15 – 15 = 0

Puzzle Corner:
a. 6 + 4 + 4 = 14 b. 2 + 4 + 2 = 8 c. 10 + 3 + 4 = 17
8 + 2 + 3 = 13 3+3+3=9 10 + 3 + 2 = 15

67
Number Rainbows—13 and 14, p. 43
1.

Fact Families - 13 and 14, p. 44

1.

Fact families with 13

10, 3, and 13
10 + 3 = 13 13 – 10 = 3
3 + 10 = 13 13 – 3 = 10

9, 4, and 13
9 + 4 = 13 13 – 9 = 4
4 + 9 = 13 13 – 4 = 9

8, 5, and 13
8 + 5 = 13 13 – 8 = 5
5 + 8 = 13 13 – 5 = 8

7, 6, and 13
7 + 6 = 13 13 – 7 = 6
6 + 7 = 13 13 – 6 = 7

2.

68
3.
Fact families with 14
10, 4, and 14
10 + 4 = 14 14 – 10 = 4
4 + 10 = 14 14 – 4 = 10

9, 5, and 14
9 + 5 = 14 14 – 5 = 9
5 + 9 = 14 14 – 9 = 5

8, 6, and 14
8 + 6 = 14 14 – 8 = 6
6 + 8 = 14 14 – 6 = 8

7, 7, and 14
7 + 7 = 14 14 – 7 = 7

4. a. 5, 8 b. 8, 9 c. 5, 6 d. 3, 5
5. a. 5 b. 8 c. 6 d. 13 e. 14 f. 12 g. 6 h. 5 i. 5
6. a. 18 cars. b. 6 more. c. 11 cherries. d. 16 apples.
7. a. 40 + 8 = 48 + 8 = 56 + 8 = 64 + 8 = 72 + 8 = 80 + 8 = 88 + 8 = 96 + 8 = 104
b. 17 + 4 = 21 + 4 = 25 + 4 = 29 + 4 = 33 + 4 = 37 + 4 = 41 + 4 = 45 + 4 = 49

Fact Families with 15, p. 47

1.
Fact families with 15
10, 5, and 15
10 + 5 = 15 15 – 10 = 5
5 + 10 = 15 15 – 5 = 10

9, 6, and 15
9 + 6 = 15 15 – 6 = 9
6 + 9 = 15 15 – 9 = 6

8, 7, and 15
8 + 7 = 15 15 – 8 = 7
7 + 8 = 15 15 – 7 = 8

2. a. 10 b. 7 c. 11 d. 6 e. 9 g. 8
3. Answers will vary: For example, think of the addition 9 + ___ = 15. Because 9 + 6 = 15, then 15 – 9 = 6.
4. 9, 12, 15, 18, 21, 24, 27, 30, 33
5. a. Jacob has 10 peaches. 7 + 3 = 10. b. Ethan has 8 books. 11 – 3 = 8, or 8 + ___ = 11.
c. Noah picked 6 more. 15 – 9 = 6 or 9 + ___ = 15. d. Sophia picked 10. 15 – 5 = 10.

6. a. 6 = 3 + 3 b. 12 = 6 + 6 c. 10 = 5 + 5
d. 18 = 9 + 9 e. 20 = 10 + 10 f. 8 = 4 + 4

7. They have 8 left. 7 + 9 = 16. Half of 16 is 8.

8. 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20

9. a. bike, $28, and kite, $30 together $ 58 b. jeans, $47, shoes, $30, and toy $10 together $ 87

69
Fact Families with 16, p. 49
1.

Fact families with 16

10, 6, and 16
10 + 6 = 16 16 – 10 = 6
6 + 10 = 16 16 – 6 = 10

9, 7, and 16
9 + 7 = 16 16 – 9 = 7
7 + 9 = 16 16 – 7 = 9

8, 8, and 16
8 + 8 = 16 16 – 8 = 8
8 + 8 = 16 16 – 8 = 8

2. a. 5, 3, 6 b. 4, 7, 5 c. 6, 5, 8 d. 8, 9, 6
3.

4. a. 6 + 3 = 9 + 3 = 12 + 3 = 15 + 3 = 18 + 3 = 21 + 3 = 24 + 3 = 27 + 3 = 30
b. 12 + 4 = 16 + 4 = 20 + 4 = 24 + 4 = 28 + 4 = 32 + 4 = 36 + 4= 40 + 4 = 44
5. a. 20 children. 24 – 2 – 2 = 20 b. Yes. $10 + $4 = $14 c. $3. $20 – $17 = $3 d. $4 more. $12 + ___ = $16
e. More girls. There is 1 more girl than boys. There are 5 boys and 7 – 1 = 6 girls.
6. a. > b. < c. > d. > e. > f. <

Fact Families - 17 and 18, p. 51

1.

Fact families with 17

10, 7, and 17
10 + 7 = 17 17 – 10 = 7
7 + 10 = 17 17 – 7 = 10

9, 8, and 17
9 + 8 = 17 17 – 8 = 9
8 + 9 = 17 17 – 9 = 8

Fact families with 18

10, 8, and 18
10 + 8 = 18 18 – 8 = 10
8 + 10 = 18 18 – 10 = 8

9, 9, and 18
9 + 9 = 18 18 – 9 = 9
9 + 9 = 18 18 – 9 = 9

70
2. a. 7, 8, 8, 9 b. 6, 7, 7, 8 c. 8, 7, 7, 6 d. 3, 4, 2, 3
3. a. > b. > c. < d. > e. < f. =
4. a. 6 b. 8 c. 9 d. 15 e. 15 f. 12 g. 8 h. 9 i. 9
5. a. The baby slept 12 hours. 4 + 2 + 3 + 3 = 12
b. Mom needs to buy two cartons of eggs. 12 + 12 = 24, which is more than 16.
She will have eight eggs left. 24 – 16 = 8
6. 100 - 90 - 89 - 84 - 80 - 78 - 70

Review, p. 53
1.

2.

3. a. 7 b. 43 c. 7 d. 9
4. a. 7 b. 7 c. 7 d. 8 e. 6 f. 6 g. 5 h. 5 i. 8
5. 75, 70, 65, 63, 60, 54, 51
6. a. Cookies Cookies your Together Can you
even/odd
you have friend has we have share evenly?
3 5 8 even yes
5 9 14 even yes
9 3 12 even yes
9 7 16 even yes

6. b. Cookies Cookies your Together Can you

even/odd
you have friend has we have share evenly?
5 6 11 odd no
7 8 15 odd no
9 4 13 odd no
1 12 13 odd no
7. IT GOT HOT IN THE HEAT.
8. a. Jane has seven more than Jack. 20 – 13 = 7 or 13 + ___ = 20 b. Sofia has 11. 14 – 3 = 11
c. Jacob has 7 pawns. 5 + 2 = 7 d. You will need to save $8 more. Think: $20 + ___ = $28.
After the neighbor pays you, you still need $6. You have $20 + $2 = $22. Think: $22 + 6 = $28.
e. I need seven more squares to get to the end of the game. You roll 5 + 6 = 11, and 11 + 7 = 18.
To get to the end, you need to roll seven on two dice. You could roll 3 and 4, or 1 and 6, or 2 and 5.

71
Math Mammoth has a variety of resources to fit your needs. All are available as economical
downloads, and most are also available as printed copies.

• Math Mammoth Light Blue Series

A complete curriculum for grades 1-7. Each grade level includes two student worktexts (A
and B), which contain all the instruction and exercises all in the same book, answer keys,
tests, cumulative reviews, and a worksheet maker. International (all metric) and South
African versions are also available.
www.MathMammoth.com/complete-curriculum.php
www.MathMammoth.com/south_africa/
www.MathMammoth.com/international/international.php

• Math Mammoth Skills Review Workbooks

These workbooks are intended to be used alongside the Light Blue series full curriculum,
and they provide additional review to the topics studied in the main curriculum, in a spiral
manner.
www.MathMammoth.com/skills-review-workbooks/

• Math Mammoth Blue Series

Blue Series books are topical worktexts for grades 1-7, containing both instruction and
exercises. The topics cover all elementary mathematics from 1st through 7th grade. These
books are not tied to grade levels, and are thus great for filling in gaps.
www.MathMammoth.com/blue-series.php

• Make It Real Learning

These activity workbooks concentrate on answering the question, "Where is math used in
real life?" The series includes various workbooks for grades 3-12.
www.MathMammoth.com/worksheets/mirl/

• Review Workbooks
Workbooks for grades 1-7 that provide a comprehensive review of one grade level of
math—for example, for review during school break or summer vacation.
www.mathmammoth.com/review_workbooks/

Free gift!

• Receive over 350 free sample pages and worksheets from my books, plus other freebies:
www.MathMammoth.com/worksheets/free.php

Lastly...

• Inspire4 is a website I've been privileged to help with:

www.inspire4.com

72