Fractions (Grade 8) Cheat Sheet by Rocketroses17

This is a cheat sheet for the fractions chapter in the Canadian curriculum of British Colombia of grade 8.

How to multiply fractions How to add fractions Fraction terms

1. If you have a mixed Example: 1 1/3 x 3/6 1. Make your Example: 3/4 + 7/8 Reciprocal = the 1/2 = proper
number fraction, turn it denominators the result of flipping the fraction because
into an improper fraction same. To do this, number upside the numerator is
find the lowest down smaller than the
2. Multiply your denomi- 1. 1 1/3 becomes 4/3 common multiple denominator
nators of both denomi-
nators The first or top 3/2 = improper
3. Multiply your 2. 3 x 6 = 18 number is the fraction because
numerators 2. Add your 1. 4 + 4 = 8. New denominumerator. Ex. 1 in the numerator is
4. Put your new 3. 4 x 3 = 12 numerators nator = 8 1/4 bigger than the
numerator over your denominator
3. Put that answer 2. 6 + 7 = 13
new denominator over your denomi- The second or 1 1/2 = mixed
5. Simplify your 4. 12/18 nator lower number is the number fraction
(im)proper fraction denominator because there's a
4. Simplify your 3. 13/8 whole number
6. Now you're done 5. 12/18 becomes 1 fraction (if and a fraction
1/2 necessary) combined to
5. You're done! 4. 1 3/4 make one fraction
How to divide fractions
How to subtract fractions When a shape is When there is a
1. If you have a mixed Example: 1
divided into equal numerator over
number fraction, turn it 1/4 ÷ 4/5 1. Make your denomi- Example: 1/2 sections of which another fraction,
into an improper fraction nators the same. To do - 1/4 some have been you divide the
2. Find the reciprocal of 1. 1 1/4 this, find the lowest shaded, the lower number, top
your second fraction becomes 5/4 common multiple of both amount of shaded number divided
denominators sections is the by bottom
3. Now multiply your 2. 4/5 numerator and the number and then
new numerators becomes 5/4 2. Subtract your second 2 + 2 = 4,
total amount of you divide the
numerator from your first new denomi-
sections, unshaded numerator by the
4. And...multiply your 3. 5 x 5 = 25 numerator nator = 4 or shaded is your new denominator
new denominators denominator
3. Put your new 2. 2 - 1 = 1
5. Put your new 4. 5 x 5 = 25 numerator over your How to simplify fractions
numerator over your denominator
new denominator 1. Write down the factors Example: 6/4
4. Simplify your fraction (if 3. 1/4 of the numerator and the
6. Simplify the 5. 25/25 necessary) denominator until you
(im)proper fraction find the lowest common
5. You're done! 4. 1/4 multiple
7. You're done 6. 1
Improper fractions into mixed numbers 2. Determine what the 1. 2, 6, 12 2,
Mixed numbers into improper fractions lowest common multiple 4, 8, 12
1. Multiply the whole Example: 1
1. Divide the numerator Example: 6/4 number by the denomi- 5/10 is
by the denominator nator 3. Divide the numerator 2. 2
2. Write down the whole 1. 6 ÷ 4 = 1.5 2. Add this number to 1. 1 x 10 = 10 and the denominator by
number answer your numerator their lowest common
multiple
3. Write down any 2. 1 3. Put that number over 2. 10 + 5 = 15
remainder above the your denominator 4. Write down the new 3. 6 ÷ 2 = 3
denominator simplified fraction and 4 ÷ 2 = 2
4. Simplify your improper 3. 15/10
4. Simplify your fraction 3. 2/4 fraction if possible 5. You're done! 4. 3/2
(if necessary)
5. You're done! 4. 3/2
5. Put your whole 4. 1/2
number in front of your
new fraction

6. You're done 5. 1 1/2