Fractions
Fractions
2
                    You Can Do Math:
                   Working With Fractions
                        Copyright & Other Notices
            Published in 2014-2015 by Answers 2000 Limited
                   Copyright © 2014-2015, Sunil Tanna
Sunil Tanna has asserted his right to be identified as the author of this Work
    in accordance with the Copyright, Designs, and Patents Act 1988.
  Information in this book is the opinion of the author, and is correct to the
best of the author's knowledge, but is provided "as is" and without warranty
 to the maximum extent permissible under law. Content within this book is
      not intended as legal, tax, financial, medical, or any other form of
                              professional advice.
     While we have checked the content of this book carefully, in any
educational book there is always the possibility of typographical errors, or
 other errors or omissions. We apologize if any such errors are found, and
would appreciate if readers inform of any errors they might find, so we can
                 update future editions/updates of this book.
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       information about Answers 2000 Limited can be found at
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    Updates, news & related resources from the author can be found at
                  http://www.suniltanna.com/fractions
  Information about other math books by the same author can be found at
                    http://www.suniltanna.com/math
                                      3
Introduction
For some time now, I have tutored both children and adults in math and
science. This book is based on my own personal experience as a tutor, and
is one of a series of books on different topics:
           If you want to find out about the other math books that I have
           written, please visit: http://www.suniltanna.com/math
           For science books that I have written, visit:
           http://www.suniltanna.com/science
Anyway, let's get started with the topic of this book... understanding and
working with fractions – also sometimes known as "simple fractions ",
"common fractions ", or "vulgar fractions ".
(2) Being able to add, subtract, multiply, and divide whole numbers.
(3) Familiarity with times tables – the better and more fluent that a student
is at their times tables, the easier that they will find fraction calculations.
To learn times tables, I suggest my book, Teach Your Kids Math:
Multiplication Times Tables , but frankly, it doesn't matter how a student
learns times tables – just so long as they do learn them.
(4) The last two chapters of this book explain how to convert fractions into
decimal numbers and vice-versa. Thus, although an understanding of
decimal numbers is not essential for most of the book, it is needed for these
two chapters. If you (or your child) isn't yet familiar with decimal numbers,
my suggestion would be to skip these topics for now, and return to them at
some point in the future after learning decimals .
You should therefore make sure that you (or your child) is familiar and
comfortable with these basics, before attempting to learn (or teach your
child) fractions!
                                        4
The Structure of This Book:
This book is intended as a guide to help adults and teens to learn and master
fractions, and for parents and teachers wishing to help younger children
learn fractions.
           The rest of the book is written for the learner – although in the
           case of younger children, my suggestion would be that the
           teacher/parent works carefully through each chapter together
           with the child. These chapters address the learner/the child
           directly as "you". I would recommend that the parent or teacher
           slowly read aloud from each chapter to the child – with a pen
           and paper handy, so any difficult points can be gone over
           immediately.
There are many online resources, as well as books and other products that
may help with learning fractions. I have placed more information about, and
links to, many of these resources at http://www.suniltanna.com/fractions
Learning Objectives for This Book:
By the end of this book, you (or your child) should be able to:
                                      5
           "complex" fractions)
           Convert a fraction to a decimal number*
           Convert a decimal number to a fraction*
* If you (or your child) is not yet familiar with decimal numbers, I would
suggest you omit these topics for now – you can always return to them in
future after learning decimals .
                                     6
Chapter 1: What is a Fraction?
A. Introducing Fractions
A fraction, sometimes known as a "common fraction ", "simple fraction "
or a "vulgar fraction " is the way in math that we represent dividing
something up into equal-sized pieces.
Imagine, for example that four friends (Aaron, Byron, Charles, and
Dominic) decide to share a pizza. They would cut the pizza into four equal
slices as shown below, and give one slice to each of the friends as shown in
the diagram below:
If we wanted to represent the amount of pizza that each of the friends got in
mathematics then we would use fractions.
                                                           In mathematics,
the amount of pizza that Aaron got is written as (sometimes also written
as 1/4). This means the pizza was divided into 4 equal-sized pieces, and
Aaron got 1 of those 4 pieces.
                                      7
In mathematics, the amount of pizza that Byron got is also written as .
Again, this is because the pizza was divided into 4 equal-sized pieces, and
Byron got 1 of those 4 pieces.
                                      8
How much pizza did Aaron, Byron and Charles get between them? Here is
the amount of pizza that these three friends got:
In mathematics, the amount of pizza that these three friends got is written as
   . This is because the pizza was divided into 4 equal-sized pieces, and
the three friends got 3 of the 4 pieces.
In each case:
Imagine now that the 4 friends are joined by 2 more people, Edward and
Frank, just in time for a second round of pizza. This new pizza is served
and is cut into 6 slices.
                                       9
                                                            In mathematics,
the amount of pizza that Aaron now gets is written as (sometimes written
as 1/6). This means the pizza was divided into 6 equal-sized pieces, and
Aaron got 1 of those 6 pieces.
I could repeat the process for each of the other people – Charles, Dominic,
Edward, and Frank – but hopefully you will be able to see that each of these
people also will now get     of a pizza. In each case:
Let's imagine that Frank says that he isn't hungry, and gives his piece to
Edward. What fraction of the pizza will Edward now get?
                                      10
Edward now gets      (also sometimes written as 2/6).
Questions:
                                        11
1. (b) Shade   of this shape:
                                12
1. (i) Shade   of this shape:
                                 13
1. (o) Shade    of this shape:
Answer:
                                     14
2. (e) What fraction of the shape is shaded?
                                     15
2. (l) What fraction of the shape is shaded?
B. Names of Fractions
Now you know how to write fractions such as , ,          , etc., you may be
wondering how to say the names of these fractions.
The most common way to say the names of fractions is to first say the value
of the numerator (the top number), and then say the value of the denominator
(the bottom number). However, the denominator is usually given as an
ordinal number (third, fifth, sixth, etc.).
For example:
                                     16
             is pronounced as "three eighths".
Here is a list of the words used for some of the most common values of the
denominator:
                                     17
Now let's try some questions.
Questions:
Answer:
                                          18
4. (d) What is the English phrase for        ?
Example Question: What is the English phrase for the shaded part of the
shape?
5. (a) What is the English phrase for the shaded part of the shape?
5. (b) What is the English phrase for the shaded part of the shape?
5. (c) What is the English phrase for the shaded part of the shape?
                                        19
5. (d) What is the English phrase for the shaded part of the shape?
5. (e) What is the English phrase for the shaded part of the shape?
5. (f) What is the English phrase for the shaded part of the shape?
5. (g) What is the English phrase for the shaded part of the shape?
5. (h) What is the English phrase for the shaded part of the shape?
5. (i) What is the English phrase for the shaded part of the shape?
5. (j) What is the English phrase for the shaded part of the shape?
                                     20
C. Fractions as Division
When we think of fractions we often think of them as being the same as
dividing an object into equal-sized pieces, and then taking one or more of
those pieces.
      Of course, we can choose to take any of the four pieces, so each of the
      following is also true:
                                     21
      Of course, we can choose any three pieces, so each of the following
      is also true:
But there is also another way to look at things when the numerator (the top
number) is more than 1. Instead of thinking of as being division of 1
object into 4, followed by multiplication by 3, we can instead think of it as
division of 3 objects by 4:
                                      22
Or, in words:
One way to visualize the fact that is the same as 3 ÷ 4 is to consider the
following diagram. In the picture, you can see that there are 3 objects
divided equally between four colors (red, blue, yellow and green).
As you can see, the red colored pieces form of one object:
Likewise, the blue colored pieces can be put together to form     of one
object:
Likewise the yellow colored pieces can be put together to form      of one
object:
                                     23
And, of course, the green colored pieces form      of one object:
Questions:
Answer:
                                       24
Now you try:
                                         25
Answers to Questions in Chapter 1
                                  26
1. (h)     (any answer with 1 section shaded and 5 unshaded is
correct)
                              27
correct)
2. (a)
2. (b)
2. (c)
2. (d)
2. (e)
2. (f)
2. (g)
2. (h)
2. (i)
2. (j)
2. (k)
2. (l)
2. (m)
2. (n)
2. (o)
3. (a)
3. (b)
3. (c)
3. (d)
3. (e)
3. (f)
           28
3. (g)
3. (h)
3. (i)
3. (j)
4. (a) two ninths
4. (b) three sevenths
4. (c) one fifth (or a fifth)
4. (d) two quarters (or two fourths)
4. (e) four tenths
4. (f) one quarter (or a quarter)
4. (g) one third (or a third)
4. (h) one half (or a half)
4. (i) four sevenths
4. (j) eight ninths
5. (a) one half (or a half)
5. (b) one half (or a half)
5. (c) three quarters (or three fourths)
5. (d) three quarters (or three fourths)
5. (e) three quarters (or three fourths)
5. (f) five eighths
5. (g) three fifths
5. (h) three fifths
5. (i) two thirds
5. (j) two thirds
6. (a) 7 ÷ 10
6. (b) 1 ÷ 4
6. (c) 5 ÷ 8
6. (d) 1 ÷ 2
                                       29
6. (e) 2 ÷ 3
6. (f) 3 ÷ 5
6. (g) 3 ÷ 7
6. (h) 3 ÷ 8
6. (i) 6 ÷ 7
6. (j) 6 ÷ 11
7. (a)
7. (b)
7. (c)
7. (d)
7. (e)
7. (f)
7. (g)
7. (h)
7. (i)
7. (j)
                30
Chapter 2: Mixed Numbers and Top Heavy Fractions
Questions:
Answer:
1. (a) Identify the mixed number represented by the shaded parts of the
shapes:
1. (b) Identify the mixed number represented by the shaded parts of the
                                      31
shapes:
1. (c) Identify the mixed number represented by the shaded parts of the
shapes:
1. (d) Identify the mixed number represented by the shaded parts of the
shapes:
1. (e) Identify the mixed number represented by the shaded parts of the
shapes:
1. (f) Identify the mixed number represented by the shaded parts of the
shapes:
1. (g) Identify the mixed number represented by the shaded parts of the
shapes:
                                     32
1. (h) Identify the mixed number represented by the shaded parts of the
shapes:
1. (i) Identify the mixed number represented by the shaded parts of the
shapes:
1. (j) Identify the mixed number represented by the shaded parts of the
shapes:
                                     33
Nothing has really changed – just how we subdivided the numbers up. In
other words – both diagrams represent exactly same number - they are
simply different ways of thinking about this same number.
Likewise, there are two ways to represent this number in math symbols:
Fractions like are called "top heavy fractions ", which refers to the fact
that the top number in the fraction (the numerator) is bigger than the bottom
number (the denominator).
Questions:
Answer:
                                     34
Now you try:
2. (a) Identify the top heavy fraction represented by the shaded parts of the
shapes:
2. (c) Identify the top heavy fraction represented by the shaded parts of the
shapes:
2. (d) Identify the top heavy fraction represented by the shaded parts of the
shapes:
2. (e) Identify the top heavy fraction represented by the shaded parts of the
shapes:
2. (f) Identify the top heavy fraction represented by the shaded parts of the
shapes:
                                          35
2. (g) Identify the top heavy fraction represented by the shaded parts of the
shapes:
2. (h) Identify the top heavy fraction represented by the shaded parts of the
shapes:
2. (i) Identify the top heavy fraction represented by the shaded parts of the
shapes:
2. (j) Identify the top heavy fraction represented by the shaded parts of the
shapes:
                                      36
           Step 2: Add the numerator (top number) of the fraction part of the
           mixed number.
           Step 3: The total becomes the new numerator (top number) in the
           top heavy fraction.
           Step 4: The denominator (bottom number) in the top heavy
           fraction as the denominator of the fraction part of the mixed
           number.
Questions:
Answer:
                                        37
3. (d) Convert      into a top heavy fraction.
Questions:
Answer:
                                     38
Now you try:
                                      39
           Step 2: The whole number part of the answer is therefore 5.
           Step 3: Since the remainder was 0, there is no fraction part in the
           answer (and Step 4 can be skipped).
Result: So is equivalent to .
Result: So is equivalent to
Questions:
5. Convert these top heavy fractions into their mixed or whole number
equivalents.
Answer:
                                     40
5. (d) Convert   into an equivalent whole or mixed number.
                                    41
Answers to Questions in Chapter 2
1. (a)
1. (b)
1. (c)
1. (d)
1. (e)
1. (f)
1. (g)
1. (h)
1. (i)
1. (j)
2. (a)
2. (b)
2. (c)
2. (d)
2. (e)
2. (f)
2. (g)
2. (h)
2. (i)
2. (j)
3. (a)
                                42
3. (b)
3. (c)
3. (d)
3. (e)
3. (f)
3. (g)
3. (h)
3. (i)
3. (j)
4. (a)
4. (b)
4. (c)
4. (d)
4. (e)
4. (f)
4. (g)
4. (h)
4. (i)
4. (j)
5. (a)
5. (b)
5. (c)
         43
5. (d)
5. (e)
5. (f)
5. (g)
5. (h)
5. (i)
5. (j)
5. (k)
5. (l)
5. (m)
5. (n)
5. (o)
5. (p)
5. (q)
5. (r)
5. (s)
5. (t)
         44
Chapter 3: Simplifying and Comparing Fractions
A. Equivalent Fractions
Look at the following:
Can you see that the proportion (or fraction) of each figure that is shaded is
exactly the same in each case?
What this means is that all the different fractions are equivalent , (we
therefore say they are "equivalent fractions "), or in mathematical symbols:
The general rule is that we can transform any fraction into an equivalent
fraction by:
                                      45
           any whole number that we like, but it must be the same for both
           numerator (top) and denominator (bottom).
Thus, for example, if we started with       , we could multiply both top and
bottom by 3, which would result in      . And we could thus say       and      are
equivalent fractions, or simply:
Questions:
Example Question:
                                       46
1. (b) Fill in the missing number in
                                       47
1. (w) Fill in the missing number in
B. Simplifying Fractions
If you are asked to simplify a fraction or express a fraction its simplest
terms or express a fraction in its lowest terms , what you are being asked
to do is find the equivalent fraction with the lowest possible denominator
(bottom number). Additionally, after doing this, if you end up with a top
heavy fraction, you would then normally want convert it to a mixed number
(or a whole number if applicable).
                                       48
           of       .
           Step 2 (again): We notice that top and bottom are again both
           divisible by 2 since both are even numbers. We therefore divide
           22 by 2 to get 11, and 132 by 2 to get 66. This gives an
           equivalent fraction of     .
           Step 2 (again): We now notice that top and bottom are both
           divisible by 11 (since both are on the 11 times table). We
           therefore divide 11 by 11 to get 1, and 66 by 11 to get 6. This
           gives an equivalent fraction of     .
           Step 2 (again): We now observe that it is not possible to repeat
           the dividing process further from       .
           Step 3: We do not have a top heavy fraction, so we do not need
           to convert it into a mixed number, the answer is still      .
                                          49
           Result: The final answer is       .    expressed in its simplest
           form as a mixed number is         .
           Note: We could also write out the series of steps that we
           performed in mathematical symbols like this:
What about if you start with a mixed number? In this case, you only need to
simplify the fraction part - you can leave the whole number part unchanged.
           Step 1: Looking only at the fraction part, we notice that top and
           bottom are both divisible by 4 since both are on the 4 times
           table. We therefore divide 8 by 4 to get 2, and 12 by 4 to get 3.
           This gives an equivalent fraction of   .
           Step 2: Still looking only at the fraction part, we now observe
           that it is not possible to repeat the dividing process further from
              .
           Step 3: Does not apply since we are dealing with the fraction
           part of a mixed number.
Questions:
                                     50
with the fraction part in its lowest terms.
Answer:
C. Comparing Fractions
If you want to compare two fractions to determine which is larger and
which is smaller, you can only easily do this if both have the same
                                      51
denominator (bottom number). If they have the same denominator, then you
can simply compare the numerators (top numbers) – the smaller fraction
will have the smaller numerator, and the larger fraction will have the larger
numerator.
For example, if we want to compare and , we can see both have the
same denominator (8), so we can then go ahead and compare the numerators
(5 and 7). We can thus say      is smaller, and       is larger.
The answer is to use a simple trick: we use the idea of equivalent fractions
to find equivalents to one or both fractions, so we can make the comparison
between fractions in which the denominators (bottom numbers) are the same
(they have a common denominator ).
                                       52
           First of all, we observe that the denominators (bottom numbers)
           in the two fractions are different. We also notice that we can't
           simply multiply one fraction's denominator to produce the other
           fraction's. This means that we are going to need to find
           equivalents of both fractions with the same "common
           denominator ". The common denominator needs to be a number
           that is both in the 6 times table (so we can convert      to it), and in
           the 9 times table (so we can convert       to it).
           For the common denominator, we can choose any number that is
           in both the 6 and 9 times tables – for example, 18, 36, 54, etc.
           Usually it's easiest to choose the lowest number possible (18 in
           this case) – but it doesn't matter if you choose one of the other
           alternatives. Let's say we choose 36...
As you can see, the process for comparing fractions is relatively simple.
However, the toughest part for many people is finding a common
denominator . If you struggle with this step, I would strongly recommend
that you practice your times tables as this will help you find the smallest
(and hence easiest) common denominators. In any case, you can always
simply multiply the two denominators together - this will always produce a
working common denominator , although it might be larger (and hence
requiring more working out) than the ideal choice.
Let's repeat the comparison between and , but using this method –
multiplying the denominators together to find a common denominator .
                                       53
           First, we observe that the denominators (bottom numbers) in the
           two fractions are different. We also notice that we can't simply
           multiply one fraction's denominator to produce the other
           fraction's. This means that we are going to need to find
           equivalents of both fractions with the same "common
           denominator ". In this example, we'll choose 54 (the result of
           multiplying the two denominators, 6 and 9, together) as our
           common denominator.
Questions:
Answer:
                                         54
3. (e) Which is the larger of   or   ?
                                     55
Answers to Questions in Chapter 3
                                      56
1. (v)   (16 was the missing number)
2. (a)
2. (b)
2. (c)
2. (d)
2. (e)
2. (f)
2. (g)
2. (h)
2. (i)
2. (j)
2. (k)
2. (l)
2. (m)
2. (n)
2. (o)
3. (a)
3. (b)
3. (c)
                                      57
3. (d)
3. (e)
3. (f)
3. (g)
3. (h)
3. (i)
3. (j)
3. (k)
3. (l)
3. (m)
3. (n)
3. (o) They are equivalent fractions – so they are both the same!
                                     58
Chapter 4: Adding fractions
Once again, the trick is to use the technique of equivalent fractions. Using
equivalent fractions, we can find equivalents to the fractions which we wish
to add, but all with the same denominator (bottom number). This same
denominator is known as the "common denominator ".
Here are the steps for adding two (or more) fractions together:
                                      59
Let's try an example:
                                        60
          Step 3: We add the numerators (3 + 2). The numerator of the
          result is thus 5, and the answer is      .
Questions:
                                      61
number or as mixed number with the fraction part in its lowest terms.
Example Question:
Answer:
1. (a)
1. (b)
1. (c)
1. (d)
1. (e)
1. (f)
1. (g)
1. (h)
1. (i)
1. (j)
1. (k)
1. (l)
1. (m)
1. (n)
1. (o)
                                     62
we must remember is that we need to use a common denominator for all the
fractions being added.
Sometimes the numbers and the multiplications can get quite tricky when
you are adding three or more fractions together. If you struggle with such
                                       63
calculations, you might find it easier to add two of the fractions together,
simplify this intermediate result if possible, then add the third fraction on to
the intermediate result to get the final answer.
Let's compare doing the same calculation two different ways: Adding          to
   to    :
First, adding all three fractions in one go – as you will see, the calculations
can be quite challenging:
                                        64
      and     becomes      .
                                         65
We also need to use the equivalent fractions method on since this
does not yet have the desired denominator (bottom number) of 54.
We thus multiply the top and bottom of    by 6, and     becomes        .
Intermediate result: .
                                 66
         since this does not yet have the desired denominator (bottom number)
         of 36. We thus multiply the top and bottom of        by 9, and   becomes
           .
Questions:
Example Question:
Answer:
2. (a)
2. (b)
2. (c)
2. (d)
2. (e)
2. (f)
2. (g)
2. (h)
                                           67
2. (i)
2. (j)
         68
Answers to Questions in Chapter 4
1. (a)
1. (b)
1. (c)
1. (d)
1. (e)
1. (f)
1. (g)
1. (h)
1. (i)
1. (j)
1. (k)
1. (l)
1. (m)
1. (n)
1. (o)
2. (a)
2. (b)
2. (c)
2. (d)
2. (e)
2. (f)
                                69
2. (g)
2. (h)
2. (i)
2. (j)
         70
Chapter 5: Subtracting Fractions
Here are the steps for subtracting one fraction from another:
                                      71
           (bottom number) of 5. Therefore, we do not need to use
           equivalent fractions. The denominator of the result is therefore 5.
           Step 3: We subtract the numerators (3 - 1). The numerator of the
           result is thus 2, and the answer is        .
           Step 4: Step 4 is not applicable for this example.
                                      72
             Step 1: Step 1 is not applicable for this example, as there are no
             mixed or whole numbers.
             Step 2: Both fractions do not already have the same denominator
             (bottom number). Therefore, we do need to use equivalent
             fractions. We choose 18 as the common denominator since this is
             in both the 6 and 9 times tables. We note that the common
             denominator, 18, will be the denominator of the result.
Questions:
Example Question:
Answer:
1. (a)
                                          73
1. (b)
1. (c)
1. (d)
1. (e)
1. (f)
1. (g)
1. (h)
1. (i)
1. (j)
         74
Answers to Questions in Chapter 5
1. (a)
1. (b)
1. (c)
1. (d)
1. (e)
1. (f)
1. (g)
1. (h)
1. (i)
1. (j)
                                75
Chapter 6: Multiplying Fractions
Multiply by
           Step 1: Does not apply since both numbers are already fractions.
           Step 2: We multiply the numerators (top numbers). Multiplying 2
           times 3 produces 6. This is the result's numerator.
           Step 3: We multiply the denominators (bottom numbers).
           Multiplying 3 times 4 produces 12. This is the result's
           denominator.
                                      76
          calculation has now become             .
          Step 2: We multiply the numerators (top numbers). Multiplying 7
          times 2 produces 14. This is the result's numerator.
          Step 3: We multiply the denominators (bottom numbers).
          Multiplying 4 times 5 produces 20. This is the result's
          denominator.
Questions:
                                    77
Example Question: Multiply      by
Answer:
1. (a) Multiply by
1. (c) Multiply by
1. (d) Multiply by
1. (e) Multiply by
1. (f) Multiply by
1. (g) Multiply by
1. (h) Multiply by
1. (i) Multiply by
1. (j) Multiply by
1. (k) Multiply by
1. (l) Multiply by
1. (m) Multiply by
1. (n) Multiply by
1. (o) Multiply by
                                     78
process that we have already looked at:
           Step 1: Does not apply since all the numbers are already
           fractions.
           Step 2: We multiply all the numerators (top numbers) together.
           Multiplying 3 times 2 times 5 produces 30. That means the
           numerator of the result is 30.
           Step 3: We multiply all the denominators (bottom numbers)
           together. Multiplying 4 times 7 times 6 produces 168. That
           means the denominator of the result is 168.
                                         79
      In other words, the calculation has now become                  .
C. Simplifying Multiplications
As you have seen, when we multiply two or more fractions together, we
often find ourselves being required to work with fairly large numbers.
The first thing that we might spot is that the numerator (top number) of
and the denominator (bottom number) of are both divisible by 9. So, we
can simplify the calculation, if we divide these two numbers by 9. If we go
ahead and do this simplification, the calculation now becomes:
                                      80
Note: When doing these types of calculations with pen and paper, many
people will often cross out the numbers exactly as shown above. You may
find it helpful to do so too. However, if you prefer, you can also write the
new calculation completely separately like this:
We might perhaps next spot that the numerator (top number) of      and the
denominator (bottom number) of are both divisible by 7. So, we can
simplify the calculation, if divide these two numbers by 7. If we go ahead
and do this simplification, the calculation now becomes:
Once again, when writing out the simplified calculation, you can either use
crossing out method as shown above, or simply write the new calculation in
full which would be:
We might next perhaps spot that the numerator (top number) of       and the
denominator (bottom number) of are both divisible by 9. So, we can
simplify the calculation, if divide these two numbers by 9. If we go ahead
and do this simplification, the calculation now becomes:
Lastly, we might spot that both numerator (top number) and the denominator
(bottom number) of       are both divisible by 2. If we go ahead and do this
simplification, the calculation now becomes:
                                     81
Or, written as a new calculation:
And if we evaluate this: the numerator (top number) of the result is 3 (by
multiplying 3 by 1 by 1), and the denominator (bottom number) of the result
is 250 (by multiplying 50 by 5 by 1). So, the final answer is     .
Questions:
Answer:
2. (a)
2. (b)
2. (c)
2. (d)
2. (e)
                                      82
2. (f)
2. (g)
2. (h)
2. (i)
2. (j)
         83
Answers to Questions in Chapter 6
1. (a)
1. (b)
1. (c)
1. (d)
1. (e)
1. (f)
1. (g)
1. (h)
1. (i)
1. (j)
1. (k)
1. (l)
1. (m)
1. (n)
1. (o)
2. (a)
2. (b)
2. (c)
2. (d)
2. (e)
2. (f)
                                84
2. (g)
2. (h)
2. (i)
2. (j)
         85
Chapter 7: Dividing fractions
A. Division of Fractions
If you want to perform a division calculation where either the number to be
divided, or the number to divide it by (the divisor), or both, are fractions,
then this is the process:
Questions:
                                          86
Example Question:
Answer:
1. (a)
1. (b)
1. (c)
1. (d)
1. (e)
1. (f)
1. (g)
1. (h)
1. (i)
1. (j)
1. (l)
1. (m)
1. (n)
1. (o)
B. Complex Fractions
You may sometimes come across what is known as "complex fractions ".
These are fractions where the numerator (top number) and/or denominator
                                    87
(bottom number) is itself a fraction.
You may not realize it yet, but you actually already know how to convert
complex fractions into normal simple fractions. You simply need remember
that all fractions are simply another way of writing division – so all you
need to do is divide the numerator (top number) of the complex fraction by
the denominator (bottom number).
Then
Then
Then
Questions:
Answer:
                                        88
Now you try:
2. (a) Simplify
2. (b) Simplify
2. (c) Simplify
2. (d) Simplify
2. (e) Simplify
2. (f) Simplify
2. (g) Simplify
2. (h) Simplify
2. (i) Simplify
2. (j) Simplify
                  89
Answers to Questions in Chapter 7
1. (a)
1. (b)
1. (c)
1. (d)
1. (e)
1. (f)
1. (g)
1. (h)
1. (i)
1. (j)
1. (k)
1. (l)
1. (m)
1. (n)
1. (o)
2. (a)
2. (b)
2. (c)
2. (d)
2. (e)
2. (f)
                                90
2. (g)
2. (h)
2. (i)
2. (j)
         91
Chapter 8: Converting Fractions to Decimals
           Step 1: We are not dealing with a top heavy fraction, so the digit
           to the left of the decimal point will be 0.
           Step 2: There are two zeroes in the denominator (100), so we
           need two digits to the right of the decimal point.
           Step 3: There are already two digits in the numerator (71), so
           that means we can simply place it to the right of the decimal
           point without inserting any extra zeroes. The answer is therefore
                                     92
           0.71.
           Step 1: We are not dealing with a top heavy fraction, so the digit
           to the left of the decimal point will be 0.
           Step 2: There are two zeroes in the denominator (100), so we
           need two digits to the right of the decimal point.
           Step 3: There is only one digit in the numerator (4), so that means
           we need to insert one extra zero between the decimal point and
           the numerator. The answer is therefore 0.04.
           Step 1: We are not dealing with a top heavy fraction, so the digit
           to the left of the decimal point will be 0.
           Step 2: There are three zeroes in the denominator (1000), so we
           need three digits to the right of the decimal point.
           Step 3: There is only one digit in the numerator (6), so that means
           we need to insert two extra zeroes between the decimal point and
           the numerator. The answer is therefore 0.006.
           Step 1: We are not dealing with a top heavy fraction, so the digit
           to the left of the decimal point will be 0.
           Step 2: There are three zeroes in the denominator (1000), so we
           need three digits to the right of the decimal point.
           Step 3: There are only two digits in the numerator (23), so that
           means we need to insert one extra zero between the decimal
           point and the numerator. The answer is therefore 0.023.
                                     93
Let's try one final example:
Questions:
                                       94
1. (i) Convert          to a decimal.
It turns out there is: For some fractions, we can simply use the technique of
equivalent fractions to convert the denominator (bottom number) to a power
of 10 – that is to a number like 10, 100, 1000, 10000, etc.
The easiest way to do this would be to convert         into the equivalent fraction
of   (by multiplying top and bottom by 2). The denominator (bottom
number) is now a power of 10, so we can then easily convert            into the
decimal 0.4.
                                         95
As we are dealing with a mixed number, we know that the whole number
part (3) will go the left of the decimal point, so we only need to deal with
the fraction part, which corresponds to the numbers to right of the decimal
point.
Once again, the easiest way to deal with    is to convert it into the
equivalent fraction of   (by multiplying top and bottom by 2). And we
know that corresponds to a 4 to the right of the decimal point. Thus, the
overall answer is 3.4.
The easiest way to do this would be to convert     into the equivalent fraction
of    (by multiplying top and bottom by 25). The denominator (bottom
number) is now a power of 10, so we can easily convert         into the decimal
0.75.
The easiest way to do this would be to convert     into the equivalent fraction
of    (by multiplying top and bottom by 5). The denominator (bottom
number) is now a power of 10, so we can easily convert         into the decimal
0.35.
The easiest way to do this would be to convert     into the equivalent fraction
of    (by multiplying top and bottom by 4). The denominator (bottom
                                      96
number) is now a power of 10, so we can easily convert      into the decimal
0.36.
Don't worry if you can't immediately spot which number you need to
multiply the top and bottom by – you will get better with practice. Also,
you should remember that this technique is a shortcut method of converting
fractions into decimals, so even if you struggle to apply this particular
technique, you can still solve the problem using the general method of
converting fractions into decimals that I will show you in the next part of
this chapter.
That said, here is a table you can use to see what to multiply the top and
bottom by to produce an equivalent fraction with a denominator which is a
power of 10:
Questions:
                                     97
2. (b) Convert    to a decimal.
2. (n) Convert to a decimal. (Hint: You may find it helpful to convert the
fraction to a mixed number before converting it to a decimal)
There is a method to do this: We rely on the fact that writing two fractions
are equivalent to division (it might seem a long time ago now, but we
looked at this way back in section C of Chapter 1 – feel free to revise this
section if necessary before continuing).
                                      98
For example, do you remember that      is equivalent to 3 ÷ 8?
Step 1: Draw the bus stop, with the number 8 in front of the bus stop, and the
number 3 underneath it.
Step 3: We divide the first digit under the bus stop (3) by 8. We write the
number of times that 8 goes into 3 above the bus stop (0), and we write the
remainder before the next digit under the bus stop (shown as the red number
3 ):
Step 4: We divide the number under the bus stop (3 0) by 8. We write the
number of times that 8 goes into 3 0 above the bus stop (3), and we write the
remainder before the next digit under the bus stop (shown as the red number
6 ):
Step 5: We divide the number under the bus stop (6 0) by 8. We write the
                                      99
number of times that 8 goes into 6 0 above the bus stop (7), and we write the
remainder before the next digit under the bus stop (shown as the red number
4 ):
Step 6: We divide the number under the bus stop (4 0) by 8. We write the
number of times that 8 goes into 4 0 above the bus stop (5). If there was a
remainder, we would write the remainder before the next digit under the bus
stop, and continue onwards until we had as many decimal places as we
want, however in this case the remainder is zero, so we can stop – we have
If you try this for yourself with different fractions, you will soon come
across examples where the division never ends with a zero remainder – you
can keep going forever. In such cases, it is normal to calculate the division
to one more decimal place than needed, and then round up or down.
Step 1: Draw the bus stop, with the number 7 in front of the bus stop, and the
number 3 underneath it.
                                     100
Step 3: We divide the first digit under the bus stop (3) by 7. We write the
number of times that 7 goes into 3 above the bus stop (0), and we write the
remainder before the next digit under the bus stop (shown as the red number
3 ):
Step 4: We divide the number under the bus stop (3 0) by 7. We write the
number of times that 7 goes into 3 0 above the bus stop (4), and we write the
remainder before the next digit under the bus stop (shown as the red number
2 ):
Step 5: We divide the number under the bus stop (2 0) by 7. We write the
number of times that 7 goes into 2 0 above the bus stop (2), and we write the
remainder before the next digit under the bus stop (shown as the red number
6 ):
Step 6: We divide the number under the bus stop (6 0) by 7. We write the
number of times that 7 goes into 6 0 above the bus stop (8) , and we write
the remainder before the next digit under the bus stop (shown as the red
number 4 ):
Step 7: We divide the number under the bus stop (4 0) by 7. We write the
number of times that 7 goes into 4 0 above the bus stop (5) , and we write
the remainder before the next digit under the bus stop (shown as the red
number 5 ):
                                    101
Step 8: We could continue calculating more and more decimal places, but
since we only needed the answer to three decimal places and have already
calculated four decimal places (we always need to calculate one extra
decimal place to know whether to round-up or round-down), we can stop.
Step 9: If we were to truncate the result after three decimal places, this
would give 0.428. However we need to look at the fourth decimal place to
see whether to round-up or round-down when truncating. Since, the fourth
decimal place is a 5, we must round-up when truncating (we round-up if it
is 5 or more), so the answer is actually 0.429.
Step 1: Draw the bus stop, with the number 7 in front of the bus stop, and the
number 5 underneath it.
Step 3: We divide the first digit under the bus stop (5) by 7. We write the
number of times that 7
goes into 5 above the bus stop (0), and we write the remainder before the
next digit under the bus stop (shown as the red number 5 ):
                                     102
Step 4: We divide the number under the bus stop (5 0) by 7. We write the
number of times that 7 goes into 5 0 above the bus stop (7), and we write the
remainder before the next digit under the bus stop (shown as the red number
1 ):
Step 5: We divide the number under the bus stop (1 0) by 7. We write the
number of times that 7 goes into 1 0 above the bus stop (1), and we write the
remainder before the next digit under the bus stop (shown as the red number
3 ):
Step 6: We divide the number under the bus stop (3 0) by 7. We write the
number of times that 7 goes into 3 0 above the bus stop (4) , and we write
the remainder before the next digit under the bus stop (shown as the red
number 2 ):
Step 7: We divide the number under the bus stop (2 0) by 7. We write the
number of times that 7 goes into 2 0 above the bus stop (2) , and we write
the remainder before the next digit under the bus stop (shown as the red
number 6 ):
Step 8: We could continue calculating more and more decimal places, but
since we only needed the answer to three decimal places and have already
calculated four decimal places (we always need to calculate one extra
decimal place to know whether to round-up or round-down), we can stop.
                                    103
Step 9: If we were to truncate the result after three decimal places, this
would give 0.714. However we need to look at the fourth decimal place to
see whether to round-up or round-down when truncating. Since, the fourth
decimal place is a 2, we must round-down when truncating (we round-up if
it is 0, 1, 2, 3, or 4), so the answer is 0.714.
Questions:
                                         104
3. (c) Convert      to a decimal.
Here are some conversions which you really should remember – they come
up all the time!
Notes:
                                    105
*    converts into a "repeating decimal " (also known as a "recurring
decimal ") – the 3s repeat on and on forever. Therefore, when converting
into a decimal we usually round to the required number of decimal places,
such as 0.33, 0.333, 0.3333, etc. You can learn more about repeating
decimals in my book, You Can Do Math: Repeating Decimals .
The conversions for tenths (and please note that some fractions involving
tenths have equivalent fifths fractions, and   is of course also equivalent to
   ) are relatively easy to remember, so hopefully you should be remember
these too:
Finally, if you can, I would also recommend trying to remember the eighths,
as these come up often enough to be worth learning:
                                      106
107
Answer to Questions in Chapter 8
1. (a) 0.0003
1. (b) 0.0431
1. (c) 56.2
1. (d) 7.098
1. (e) 3.33
1. (f) 0.333
1. (g) 3.3
1. (h) 3.3
1. (i) 3.33
1. (j) 5.42
1. (k) 5.02
1. (l) 5.002
1. (m) 5.021
1. (n) 5.321
1. (o) 10.10 (or 10.1)
2. (a) 0.28
2. (b) 0.15
2. (c) 0.14
2. (d) 2.25
2. (e) 6.6
2. (f) 0.4
2. (g) 1.6
2. (h) 4.15
2. (i) 3.28
2. (j) 0.525
2. (k) 0.18
2. (l) 1.06
                                   108
2. (m) 0.98
2. (n) 1.4
2. (o) 4.96
3. (a) 0.833 (rounded to three decimal places)
3. (b) 1.875 (exact answer)
3. (c) 5.222 (rounded to three decimal places)
3. (d) 1.857 (rounded to three decimal places)
3. (e) 0.444 (rounded to three decimal places)
3. (f) 1.375 (exact answer)
3. (g) 0.556 (rounded to three decimal places)
3. (h) 1.833 (rounded to three decimal places)
3. (i) 0.429 (rounded to three decimal places)
3. (j) 0.778 (rounded to three decimal places)
3. (k) 0.222 (rounded to three decimal places)
3. (l) 0.625 (exact answer)
3. (m) 3.667 (rounded to three decimal places)
3. (n) 3.5 (exact answer)
3. (o) 1.75 (exact answer)
                                    109
Chapter 9: Converting Decimals to Fractions
Fact 1: The first digit to the right of the decimal point is tenths, the second
digit is hundredths, the third digit is thousandths, and so on.
Fact 2: We can read all the digits to the right of the decimal point together
as one number.
                                         110
           fraction      .
           Likewise if encounter 0.036, we should think of it as not as 3
           hundredths and 6 thousandths, but rather as 36 thousandths, and
           thus as the fraction       .
           Likewise if encounter 0.408, we should think of it as not as 4
           tenths and 8 thousandths, but rather as 408 thousandths, and thus
           as the fraction        .
           Likewise if encounter 0.574, we should think of it as not as 5
           tenths, 7 hundredths and 4 thousandths, but rather as 574
           thousandths, and thus as the fraction         .
Fact 3: When dealing with a decimal with digit(s) to the left of the decimal
point, these simply form the whole number part of a mixed number.
Fact 4: Many fractions can be simplified. This applies whether the fraction
represents the entire number, or just the fraction part of a mixed number.
                                          111
           divisible by 5, and the faction be simplified to     .
Questions:
                                      112
1. (k) Convert 2.18 to a fraction.
1. (l) Convert 3.001 to a fraction.
1. (m) Convert 4.01 to a fraction.
1. (n) Convert 9.09 to a fraction.
1. (o) Convert 5.5 to a fraction.
1. (p) Convert 2.75 to a fraction.
1. (q) Convert 3.1 to a fraction.
1. (r) Convert 3.10 to a fraction.
1. (s) Convert 10.10 to a fraction.
1. (t) Convert 0.4 to a fraction.
                                      113
Answer to Questions in Chapter 9
1. (e)
1. (f)
1. (h)
1. (l)
1. (m)
1. (n)
1. (q)
                                    114
115
Conclusion
Well done! If you have worked your way through this whole book, you now
should understand fractions, as well as mastered all the basic arithmetic
operations (addition, subtraction, multiplication, and division) using
fractions.
Keep up the good work, and keep practicing and learning! You are well on
the way to become a math wizard!
For more fractions fun (and to learn about advanced fractions), please go to
http://www.suniltanna.com/fractions
And if you enjoyed this book or it helped you, please post a positive
review on Amazon!
To find out about other educational books that I have written, please go to:
Thanks!
                                     116
اﻟﻤﺤﺘﻮﯾﺎت
Introduction                                         4
Chapter 1: What is a Fraction?                       7
Chapter 2: Mixed Numbers and Top Heavy Fractions    31
Chapter 3: Simplifying and Comparing Fractions      45
Chapter 4: Adding fractions                         59
Chapter 5: Subtracting Fractions                    71
Chapter 6: Multiplying Fractions                    76
Chapter 7: Dividing fractions                       86
Chapter 8: Converting Fractions to Decimals         92
Chapter 9: Converting Decimals to Fractions        110
Conclusion                                         116
117