CH 7
CH 7
Fractions
   7.1 Introduction
   Subhash had learnt about fractions in Classes IV and V, however he
   was not very confident, so whenever possible he would try to use
   fractions. One occasion was when he forgot his lunch at home. His
   friend Farida invited him to share her lunch. She had five pooris in her
   lunch box. So Subhash and Farida took two pooris each. Then Farida
   made two equal halves of the fifth poori and gave one-half to Subhash
   and took the other half herself. Thus, both Subhash and Farida had 2
   full pooris and one-half poori.
7.2 A Fraction
Let us recapitulate the discussion
  A fraction means a part of a group or of a region.
   5
     is a fraction. We read it as “five -twelfths”.
  1 2
  What does “12” stand for? It is the number of equal parts into which the
whole has been divided.
  What does “5” stand for? It is the number of equal parts which have been
taken out.
           Mathematics
    170
      Here 5 is called the numerator and 12 is called the
    denominator.
                                                           3
        Name the numerator of the fraction                   . What is the
                                                           7
                          4
    denominator of          ?
                         1 5
    2
           Play this Game:
    You can play this game with your friends.
     Take many copies of the grid as shown here.
                                     1
    Consider any fraction, say         .
                                     2
                                               1
        Each one of you should shade             of the grid.
                                               2
7       The condition is that no two of you should shade same pattern.
                         EXERCISE 7.1
    1. Write the fraction representing the shaded portion.
( i ( )i i ) ( i ( ii v ) i )
                (v)             (              v      i(        v)   i           i(   )v        i     i   i       )
                                                                                   Fractions
                                                                                                   171
( i x ) (x) ( x i )
( x (xiii) i i )
              ((      1               ii((    2 ii         ii    ))   )(
                                                                      )(       1        ii               ii       ii
             ((                      ii((       i          i     )    )(                ii               ii       ii
                      6                       4                                3
                      1         1                      3
            This is     This is          This is
                      2         4                      4
     4. What fraction of a day is 8 hours?
     5. What fraction of an hour is 40 minutes?
     6. Arya, Abhimanyu, and Vivek shared lunch. Arya brought two sandwiches, one
        made of vegetable and one of jam. The other two boys forgot to bring their
        lunch. Arya agreed to share his sandwiches so that each person will have an
        equal share of each sandwich.
        (a) How can Arya divide his sandwiches so that each person has an equal share?
7       (b) What part of a sandwich will each boy receive?
     7. Kanchan has three frocks that she wears while playing. The material is good,
        but the colours are faded. Her mother buys some blue dye and uses it on two of
        the frocks. What fraction of the Kanchan’s frocks did her mother dye?
     8. Write the natural numbers from 2 to 12. What fraction of them are prime numbers?
     9. Write the natural numbers from 102 to 113. What fraction of them are prime
        numbers?
    10. What fraction of these circles have X’s in them?
( a ( ) b ( ) c )
    11. Dinesh, Sumit, Ram, Joy, Marshal, Imran, Jayant, Babu, Kabir and Rohan
        decide to play basketball. The first five boys are in the first team and the rest are
        in the second team. What fraction of the boys is in the first team?
                                                                   Fractions
                                                                               173
12. Kristin received a CD player for her birthday. She has been collecting CDs
    since then. She bought 3 CDs and received 5 others as gifts. What fraction of
    her total CDs did she buy?
                                                                                     7
                                   1
equal parts and show 1 part as       (as shown in the Fig 7.5).
                                   2
      0                                 1                                 1
                                        2
                                     Fig 7.5
             1
  To show      on a number line, into how many equal parts should the gap
             3
between 0 and 1 be divided? We divide the gap between 0 and 1 into 3 equal
                               1
parts and show one part as       (as shown in the Fig 7.6)
                               3
      0                    1                                              1
                           3
                                     Fig 7.6
             2                    2
  Can we show on this number line? means 2 parts out of 3 parts as
             3                    3
shown (Fig 7.7).
          Mathematics
    174
          0                   1                  2                   1
                              3                  3
                                      Fig 7.7
                                       0    3
      Similarly, how would you show      and on this number line?
                                       3    3
      0                          3
        is the point zero whereas is 1 whole, which can be shown by the
      3                          3
    point 1 (as shown in Fig 7.8)
          0                   1                  2                   3
            ( = 0 )                                                    ( = 1 )
          3                   3       Fig 7.8
                                                 3                   3
                              3
7     So if we have to show     on a number line, then, into how many equal
                              7
                                                                  3
    parts should the gap between 0 and 1 be divided? If P shows     then how
                                                                  7
                                                         0    7
    many equal divisions lie between 0 and P? Where do     and lie?
                                                         7    7
                3
     1. Show      on a number line.
                5
                 1   0   5     1 0
     2. Show       ,   ,   and   on a number line.
                1 0 1 0 1 0 1 0
     3. Can you show any other fraction between 0 and 1?
        Write five more fractions that you can show and depict them on the
        number line.
     4. How many fractions lie between 0 and 1? Think, discuss and write
        your answer?
                                                              Fractions
                                                                          175
7.4 Proper Fractions
You have now learnt how to locate fractions on a number line. Locate the
            3 1 9 0 5
fractions    , , , , on separate number lines.
            4 2 1 0 3 8
  Does any one of the fractions lie beyond 1?
  All these fractions lie to the left of 1as they are less than 1. Why?
  In a proper fraction, the numerator is less than the denominator.
                        5
      Anagha said in      , the numerator is bigger than the denominator. The
                        4
    fractions, where the numerator is bigger than the denominator are called
    improper fractions.
                              3 1 2 1 8
      Thus, fractions like     ,   , are all improper fractions.
                              2 7 5
                                                                     Fractions
                                                                                 177
 1. Write five improper fractions with denominator 7.
 2. Write five improper fractions with numerator 11.
                                                                 5
  The fraction of apples received by each of the friends is        . However, as
                                                                 4
Anagha said, it is also one apple and one fourth more as shown in the picture
(Fig 7.9).
               This is 1                                         1
                                           Each of these is
                (one)                                            4
                                                 (one fourth)
                                                                                       7
                                 Fig 7.9
            1                1                  5
  Thus, 1     is written as 1 and is the same as .
            4                4                  4
                                                    1
  Recall the pooris eaten by Farida. She got 2        poories (Fig 7.10).
                                                    2
  i.e.,
          This is 1                                              1
                                  Fig 7.10
                                                     This is 2
                                                                 2
                                             1
  How many shaded halves are there in 2 ? There are 5 shaded halves.
                                             2
          Mathematics
    178
                            5                        5
      So, the fraction is     . Obviously this is not .
                            2                        4
                            1      1
      Fractions such as 1     and 2 are          Do you know?
                            4      2
                                    The grip-sizes of tennis racquets are often
    called Mixed Fractions. A mixed in mixed numbers. For example one size
    fraction has a combination of a
                                         7              3
    whole and a part.               is “3 inches” and “4 inches” is another..
                                         8              8
      Where do you come across
    mixed fractions? Give some
    examples.
    Example 1 : Express the following as mixed fractions :
                          1 7            1 1            2 7         7
                    (a)            (b)            (c)         (d)
                           4              3              5          3
7   Solution      : (a)
                          1 7
                                   4 1 7
                                          4
                           4
                                         1 6
                                         1
                                         1            1
                    i.e., 4 whole and      more, or 4
                                         4            4
                          1 1             3
                    (b)            3 1 1
                           3
                                          9
                                          2
                                         2            2
                    i.e., 3 whole and      more, or 3
                                         3            3
                                                                       Fractions
                                                                                   179
                  2 7            5
            (c)      5       2       7
                   5
                              2 5
                                 2
                                         2           2
            i.e., 5 whole and              more, or 5 .
                                         5           5
                7                        2
            (d)                  3       7
                3
                                         6
                                         1
                             7    1
            We write           =2
                             3    3
                                                                                         7
                       7   6   1   1   1
              A l t e r n a t e l y , 2 2
                       3   3   3   3    3
            Thus, we can express an improper fraction as a mixed
            fraction by dividing the numerator by denominator to obtain
            the quotient and the remainder. Then the mixed fraction will
                                                     Remainder
            be written as Q u o t i e n t                   .
                                                      Diviser
Example 2 : Express the following mixed fractions as improper
            fractions :
                     3                       1                     3
            (a) 2                (b) 7                     (c) 5
                     4                       9                     7
                     3   (    2 4         )          3 1   1
Solution   : (a) 2            o                  r
                     4          4                     4
          Mathematics
    180
                              1 ( 7 9 ) 1 6 4
                    (b) 7         o    r
                              9     9    9
                              3     (   5 7   )       3 3      8
                    (c) 5               o         r
                              7           7            7
                    Thus, we can express a mixed fraction as an improper
                    fraction by multiplying the whole with the denominator and
                    adding the numerator to it. Then the improper fraction will
                    be
                        (Whole × Denominator) + Numerator
                                  Denominator
                            EXERCISE 7.2
    1. Draw number lines and locate the points on them.
7      (a)
             1 1
              , ,
                        3
                        ,
                             4    1 2 3 7
                               (b) , , ,                       (c)
                                                                     2 3 8 4
                                                                      , , ,
             2 4        4    4    8 8 8 8                            5 5 5 5
    2. Express the following as mixed fractions:
             2 0                  1 1                   1 7
       (a)                  (b)                   (c)
              3                    5                     7
           2 8              1 9                 3 5
       (d)              (e)                (f )
           5                 6                   9
    3. Express the following as improper fractions:
               3                    6                      5
       (a) 7                (b) 5                 (c) 2
               4                    7                      6
             3                      3                      4
       (d) 1 0              (e) 9                 (f ) 8
             5                      7                      9
                                                            Fractions
                                                                        181
7.6 Equivalent Fractions
Look at all these representations of fraction (Fig 7.11).
                                 Fig 7.11
                        1 2 3
  These fractions are    , , representing the parts taken from the total
                        2 4 6
number of parts. If we place the pictorial representation of one over the
other they are found to be equal. Do you agree?
  These fractions are called equivalent fractions. Think of three more
fractions that are equivalent to the above fractions.
                                                                              7
          1     2
 1. Are     a n d equivalent? Give reason.
          3     7
          2    2
 2. Are     a n d equivalent? Give reason.
          5    7
          2    6
 3. Are     a n d equivalent? Give reason.
          9 2 7
 4. Give example of four equivalent fractions.
 5. Identify the fractions in each.
    Are these fractions equivalent?
           Mathematics
    182
    Understanding equivalent fractions
      1 2 3 3 6
       , , , . . . , . . are
                         . , all equivalent fractions.
      2 4 6 7 2
      They represent the same part of a whole.
    Think, Discuss and Write
    Why do the equivalent fractions represent the same part of a whole? How
    can we obtain one from the other?
                   1    2
      Consider       a n d. The numerator of the second fraction is twice the
                   2    4
    numerator of the first and the denominator of the second is also twice that
    of the first.
      What does this mean?
                     2 1 × 2
      This means      =
                     4 2 × 2
7     Similarly
                   3 1 × 3 1
                    =   =
                   6 2 × 3 2
              1 1 × 4 4
      and      =   =
              2 2 × 4 8
      To find an equivalent fraction of a given fraction, you may multiply
    both the numerator and the denominator of the given fraction by the
    same number.
                                                    1
          Rajni says that equivalent fractions of     are :
                                                    3
          1    2     2 1 3 3 1  4 4
                    ,    ,          and many more.
          3    2    6 3 3 9 3 4 1 2
          Do you agree with her? Explain with reasons.
                                                                   Fractions
                                                                               183
Another way
Is there any other way to obtain equivalent fractions? Look at the (Fig 7.12) :
           4                                   2
             is shaded here.                     is shaded here.
           6                      Fig 7.12     3
                                   2 6
                    Thus, we get    =
                                   5 1 5
                    Can you show this pictorially?
                                                          1 5
    Example 4 : Find the equivalent fraction of              with denominator 7.
                                                          3 5
                              1 5
    Solution      : We have     =
                              3 5     7
                    We observe the denominators. Since 35 ÷ 5 = 7, so we divide
7                   the numerator of
                                          1 5
                                             also by 5.
                                          3 5
                              1 5 1 5 ÷ 5 3
                    We have     =    =
                              3 5 3 5 ÷ 5 7
                                                          1 5 3
                    Thus, replacing        by 3, we get     =
                                                          3 5 7
    An Interesting Fact
    There is something quite interesting about equivalent fractions. Complete
    the table given. The first two rows have been done. (Nr. is for numerator
    and Dr. for denominator).
                                                                Fractions
                                                                            185
  Equivalent           Product of              Product of         Are the
   fractions     the Nr. of the1st and     the Nr. of the 2nd     products
                   the Dr. of the 2nd        and the Dr. of        equal?
                                                the 1st
     1 3
      =              1 × 9 = 9.            3 × 3 = 9.               Yes
     3 9
    4 2 8
     =             4 × 35 = 140           5 × 28 = 140              Yes
    5 3 5
    1 4
     =
    4 1 6
    2 1 0
     =
    3 1 5
    3 2 4
     =
    7 5 6
   What do we infer? The product of the numerator of the first and the            7
denominator of the second is equal to the product of denominator of the
first and the numerator of the second in all these cases. You can try this
with other fractions as well. Did you find any pair of fractions for which it
does not happen? This rule is sometimes helpful to find equivalent fractions.
                                                  2
Example 5 : Find the equivalent fraction of         with denominator of 63.
                                                  9
                           2
Solution     : We have       =
                           9 6 3
               For this, we should have, 9    2    6    3   .
                   9       2   6   3
               S o ,
                       9       9
                               2   6  3    2     1   4
               T h e r e f o r e , 1 4 i . e . ,
                                 9   9       6     3
          Mathematics
    186
    7.7 Simplest Form of a Fraction
                         3 6
    Given the fraction     , let us try to get an equivalent fraction in which the
                         5 4
    numerator and the denominator have no common factor except 1.
      How do we do it? We see that both 36 and 54 are divisible by 2.
      3 6 3 6 2 1 8
      5 4 5 4 2 2 7
      But 18 and 27 also have common factors other than one.
      The common factors are 1, 3, 9.
                   1 8 1 8 9 2
      Therefore,
                   2 7 2 7 9 3
                                                                        2
      Since 2 and 3 have no common factor, we get the fraction            in the
                                                                        3
7   simplest form.
      A fraction is said to be in the simplest (or lowest) form if its
    numerator and denominator have no common factor except 1.
    The shortest way :
    The shortest way to find the equivalent fraction
    in the simplest form is to find the HCF of the
    numerator and denominator. Then divide both
    of them by the HCF and get the equivalent
    fraction in the simplest form.
                                                                        Fractions
                                                                                    187
               3 6                                    A game
  Consider       .
               2 4              The equivalent fractions given here are quite
   The HCF of 36 and 24         interesting. Each one of them uses all the digits from
is 12.                          1 to 9 once!
             3 6 1 2 3                   2     3 5 8
                                              =   =
  Therefore,                             6    9 1 7 4
             2 4 1 2 2
                                         2     3 7 9
  Thus the idea of HCF                        =   =
                                    4         6 1 5 8
helps us to reduce a
fraction to its lowest form. Can you find two more such equivalent fractions?
 2. Is
           1 6 9
               in its simplest form?                                                      7
           2 8 9
                     EXERCISE: 7.3
1. Write the fractions. Are all these fractions equivalent?
(a)
    (b)
          Mathematics
    188
    2. Write the fractions and pair up the equivalent fractions from each row.
              4 5 1 5              1 8
        (d)                  (e)
              6 0                  2 4   4
                                         3
    4. Find the equivalent fraction of     having
                                         5
        (a) denominator 20            (b) numerator 9
        (c) denominator 30            (d) numerator 27
                                         3 6
    5. Find the equivalent fraction of     with
                                         4 8
       (a) numerator 9            (b) denominator 4
    6. Check whether the given fractions are equivalent:
              5 3 0                   3 1 2                       7   5
        (a)    ,               (b)     ,                   (c)      ,
              9 5 4                  1 0 5 0                     1 3 1 1
                                                                   Fractions
                                                                               189
7. Reduce the following fractions to simplest form :
         4 8                   1 5 0               8 4
   (a)                   (b)                 (c)
         6 0                    6 0                9 8
         1 2                   7
   (d)                   (e)
         5 2                   2 8
8. Ramesh had 20 pencils, Sheelu had 50 pencils and Jamaal had 80 pencils. After
   4 months, Ramesh used up 10 pencils, Sheelu used up 25 pencils and Jamaal
   used up 40 pencils. What fraction did each use up? Check if each has used up an
   equal fraction of their pencils?
9. Match the equivalent fractions and write two more for each :
            52   0              2
         (  )    i
               ( a )
        4   0    0              3
        1   8   0               2
     ( i i ) (b )
        2   0    0              5
                                                                                     7
        6   6   0               1
    ( i i i ) (c )
        9   9   0               2
        1   8    0              5
    ( i v ) (d )
        3   6    0              8
        2   2    0              9
     (  v )   ( e)
        5 5   0    1                0
Fig 7.13
 1. You get one-fifth of a bottle of juice and your sister gets one-third
    of a bottle of juice. Who gets more?
                        3 2
      Therefore,         >
                        4 3
                              EXERCISE 7.4
    1. Write each fraction. Arrange them in ascending and descending order using correct
       sign ‘<’, ‘=’, ‘>’ between the fractions:
(a)
7 (b)
                     2     4    8    6
        (c) Show       ,     ,    and on the number line. Put appropriate signs between
                     6     6    6    6
              the fractions given
              5         2        3        0         1   6     8    5
                          ,                 ,             ,
              6         6        6        6         6   6     6    6
    2. Compare the fractions and put an appropriate sign.
              3     5                 1         1
        (a)                     (b)
              6     6                 7         4
              4     0                        3  4
        (c)                     (d)
              5     5                       2 0 2 0
                                                                                         Fractions
                                                                                                     195
3. Make five more such pairs and put appropriate signs.
4. Name the fractions and arrange them in ascending order :
5. Look at the figures and write ‘<’ or ‘>’, ‘=’ between the pairs of fractions.
             0                                                                             1
             1                                                                             1
             0                                         1                                   2
             2                                         2                                   2
                                                                                                           7
             0                         1                       2                           3
             3                         3                       3                           3
             0               1                         2                 3                 4
             4               4                         4                 4                 4
             0           1                     2           3                 4             5
             5           5                     5           5                 5             5
             0       1                 2               3       4                 5         6
             6       6                 6               6       6                 6         6
         1       1                         3       2                         2       2
   (a)                           (b)                               (c)
         6       3                         4       6                         3       4
         6       3                         0       0                         5       5
   (d)                           (e)                               (f)
         6       3                         1       6                         6       5
   Make five more such problems and solve them with your friends.
           Mathematics
    196
    6. How quickly can you do this? Fill appropriate sign. ( <, =, >)
               1     1                   2        3                  3    2
        (a)                       (b)                        (c)
               2     5                   4        6                  5    3
               3     2                   3        6                  7    3
        (d)                       (e)                        (f)
               4     8                   5        5                  9    9
               1     2                   6 4                         3    7
        (g)                       (h)                        (i)
               4     8                  1 0 5                        4    8
                6 4                      5    1       5
        ( j)                      (k)
               1 0 5                     7    2       1
    7. The following fractions represent just three different numbers. Separate them into
       three groups of equivalent fractions, by changing each one to its simplest form.
                2                        3                           8
        (a)                       (b)                        (c)
               1 2                      1 5                         5 0
7       (d)
                1 6
                                  (e)
                                        1 0
                                                             (f )
                                                                    1 5
               1 0 0                    6 0                         7 5
               1 2                      1 6                         1 2
        (g)                       (h)                        (i)
               6 0                      9 6                         7 5
               1 2                       3                           4
        ( j)                      (k)                        (l)
               7 2                      1 8                         2 5
    8. Find answers to the following. Write and indicate how you solved them.
                   5         4                     9         5
        (a) Is       equal to ?         (b) Is       equal to ?
                   9         5                    1 6        9
                   4          1 6                  1           4
        (c) Is       equal to   ?       (d) Is       equal to    ?
                   5          2 0                 1 5         3 0
                                                                              1
    9. Ila read 25 pages of a book containing 100 pages. Lalita read            of the same
                                                                              2
        book. Who read less?
                                                                    Fractions
                                                                                197
                          3                                       3
10. Rafiq exercised for      of an hour, while Rohit exercised for of an hour. Who
                          6                                       4
    exercised for a longer time?
11. In a class A of 25 students 20 passed in first class; in another class B of 30
    students, 24 passed in first class. In which class were there more fraction of
    students getting first class?
2
    1                                   1
      litre of milk in the morning and 1 litre of milk in the evening. What
                                                                                      7
    2                                   2
is the total amount of milk she uses in the stall?
                                                  1
    Or Shekhar ate 2 chapatis for lunch and 1       chapati for dinner. What is
                                                  2
the total number of chapatis he ate?
  Clearly both the situations require the fractions to be added. Some of
these additions can be done orally and the sum can be found quite
easily.
      In all these you can also find out the remaining part. In the first problem
    the apple remaining, in the second the fraction of the stones left to be
    picked and in the third the remaining fraction of the table to be made.
7
    Make ten such problems with your friends and solve them.
    7.10.1 Adding or Subtracting like Fractions
    All fractions cannot be added orally. We need to know how they can be
    added in different situations and learn the procedure for it. We begin by
    looking at addition of like fractions.
       Take a 7 × 4 grid sheet (Fig 7.14). The sheet has seven boxes in each row
    and four boxes in each column .
       How many boxes are there in total?
       Colour five of its boxes in green.
       What fraction of the whole is the green region?
       Now colour another four of its boxes in yellow.
       What fraction of the whole is this yellow region?
       What fraction of the whole is coloured
    altogether?                                                  Fig 7.14
                                                                      Fractions
                                                                                  199
                                 5   4   9
  Does this explain that                   ?
                                 2 8 2 8 2 8
Look at more examples
In Fig 7.15 (i) we have 2 quarter parts of the figure shaded. This means we
                                     1
have 2 parts out of 4 shaded or        of the figure shaded.
                                     2
  That is, 1     1    2   1.
           4     4    4   2
  Look at Fig 7.15 (ii)
                                                                                        7
                             1          1    1   3     1
  Fig 7.15 (ii) demonstrates                             .
                             9          9    9   9     3
   What do we learn from the above examples? The sum of two or more
like fractions can be obtained as follows:
   Step 1 Add the numerators.
   Step 2 Retain the (common) denominator.
                                            Result of Step 1
  Step 3       Write the fraction as:
                                            Result of Step 2
                     3    1          3           1 3 1 4
  Let us thus add      and . We have
                     5    5          5            5 5  5
                                     7     3
  So, what will be the sum of          and ?
                                    1 2   1 2
           Mathematics
    200
                                                1 1 1
     2. What do we get when we do this
                                               1 2 1 2 1 2
          How will we show this pictorially? Using paper folding?
     3. Make 10 more examples of problems given in 1 and 2 above.
          Solve them with your friends.
                                         Fig 7.16
               5    2 5 2 3 1
  We find that             o r
               6     6 6 6   2
  (Is this not similar to the method of adding like fractions?)
  Thus, we can say that the difference of two like fractions can be obtained
as follows:
  Step 1 Subtract the smaller numerator from the bigger numerator.
  Step 2 Retain the (common) denominator.
                                                                                 7
                                     Result of Step 1
  Step 3    Write the fraction as:
                                     Result of Step 2
                                      3      8
            Can we now subtract         from ?
                                     1 0    1 0
                                     7    3
 1. Find the difference between        and .
                                     4    4
 2. Mother made a gud patti in a round shape. She divided it into 5 parts.
    Seema ate one piece from it. If I eat another piece then how much
    would be left?
 3. My elder sister divided the watermelon into 18 parts. I ate 7 out
    them. My friend ate 4. How much did we eat between us? How much
    more of water melon did I eat compared to my friend? What amount
    of water melon remained?
 4. Make five problems of this type and solve them with friends.
          Mathematics
    202
                        EXERCISE 7.5
    1. Write these fractions appropriately as additions or subtractions :
(a) .... =
                              .      .     .   .
        (b)                                                    =
                             . . . .                       =
        (c)
7                                          +                                     =
        (a)
                              +                        +                             =
        (b)
    3. Solve :
               1  1                         8  3                     7       5
        (a)                          (b)                       (c)
              1 2 1 2                      1 5 1 5                   7       7
              1 2 1                        5       6                 1 2 7
        (d)                          (e)                       (f)
              2 2 2 2                      9       9                 1 5 1 5
              5   3                        3       4                     2           3
        (g)                          (h)                       (i) 1             1
              8   8                        5       5                     3           3
                                                                                Fractions
                                                                                            203
          1         0                           0   0                 1 6 7
   ( j)                                   (k)                   (l)
          4         4                           2   2                  5 5
              1   2                                 1 2
   (m) 2        1                         (n) 3 –
              3   3                                  5
                                    2
4. Shubham painted                    of the wall space in his room. His sister Madhavi helped
                                    3
                        1
   and painted            of the wall space. How much did they paint together?
                        3
                         1                                1
5. Kamlesh bought 3        kg sugar whereas Anwar bought 2 kg of sugar. Find the
                         2                                2
   total amount of sugar bought by both of them.
6. Fill in the missing fractions.
           7            3                           3   5
   (a)                                   (b)
          1 0           1       0                   2 1 2 1
                3           3                        5 1 2
                                                                                                  7
   (c)        –                          (d)
                6           6                       2 7 2 7
                       3                            1
7. The teacher taught    of the book, Mahesh revised more on his own. How
                       5                            5
   much does he still have to revise?
                                5
8. Javed was given                of a basket of oranges. What fraction of oranges was left in
                                7
   the basket?
                    1 1 5 2 5 – 2 3
      Therefore,     –    –
7                   2 5 1 0 1 0 1 0 1 0
                                        3     5
    Example 6 : Let us now subtract       from .
                                        4     6
    Solution       : We have, LCM (4, 6) = 12 [Remember we have done this to
                     find equivalent fractions].
                                  5 3 5 2 3 3 1 0 9 1
                     Therefore,    –     –     –
                                  6 4 6 2 4 3 1 2 1 2 1 2
               2    3
     1. Add      and .
               5    7
                     2     5
     2. Subtract       from .
                     5     7
                       4       5
Example 7 : Add 2        and 3
                       5       6
                   4       5       4        5        4       5
Solution     : 2       3       2        3        5
                   5       6       5        6        5       6
               Here again we need to make equivalent fractions. You can
               use any of the methods that you have learnt.
                                                  4 2 4          4 × 6
               Equivalent fraction for,
                                                  5 3 0          5 × 6
                           5 2 5                5 × 5
               and for
                           6 3 0                6 × 5                                      7
                                                     4   5
               The sum is therefore 5
                                                     5   6
                                                                          1
                       2 4 2 5                  4 9                  3 0 4 9
               = 5                      5
                         3 0                    3 0
                                                                          3 0
                                                                          1 9
                           1 9                  1 9
               =5      1               =6
                           3 0                  3 0
Think, Discuss and Write
 Can you find some other procedures to solve this problem?
                       2   1
Example 8 : Find 4       2
                       5   5
          Mathematics
    206
    Solution      : The whole numbers 4 and 2 and the fractional numbers
                        2    1
                          a n d can be subtracted separately. (Note that 4 > 2 and
                        5    5
                        2     1
                                )
                        5     5
                               2            1           2      1         1     1
                        S     o         ,           4     2    4     2     2    2
                               5            5           5      5         5     5
                                            1  5
    Example 9 : Simplify: 8                   2 .
                                            4  6
                                                1       5
    Solution      : Here 8 > 2 but                        . It can be solved as follows:
                                                4       6
                            1 38 ×3 4 +5 1 2 × 6                   + 5 1 7
                        8     = =       a n d                       2 = =
                            4    4       4    6                     6   6
7                    Now,
                                3 3 1 7 3 3 3 1 7                   2
                                                                         (Since LCM (4,5)=12)
                                 4 6 1 2 1 2
                                       9 9 3 4 6                     5 5
                                                                    5
                                         1 2 1 2                     1 2
                 1       2                                                2        6
     1. Add 2      and 3                                 2. Subtract 2      from 5
                 5       6                                                3        7
                            EXERCISE 7.6
    1. Solve
             2   1                   3  7                      4    2                5   1
       (a)                   (b)                         (c)                   (d)
             3   7                  1 0 1 5                    9    7                7   3
             2   1                  4       2                  3 1                   5 1
       (e)                   (f )                        (g)    –              (h)    –
             5   6                  5       3                  4 3                   6 3
                                                                            Fractions
                                                                                        207
          7 2                1 1                 1 1                       6 1
   (i)     –           (j)    –            (k)    –              (l)        –
         1 0 5               2 3                 2 6                       8 3
         2   3       1     1   1   1                 1   2                 2   1
   (m)                 (n)                 (o) 1       3         (p) 4       3
         3   4       2     2   3   6                 3   3                 3   4
         1 6 7               4 1                1  2                  2  2
   (q)     –           (r)    –            (s) 2 – 1             (t) 3 – 1
          5 5                3 2                3  3                  3  3
                    2                           3
2. Sarita bought      metre of ribbon and Lalita metre of ribbon. What was the
                    5                           4
   total length of the ribbon they bought?
                      1                                     1
3. Naina was given 1     piece of cake and Najma was given 1 piece of cake.
                      2                                     3
   Find the total amount of cake given to both of them.
                                   5   1                1    1         1       1
4. Fill in the boxes : (a)                   (b)                 (c)
                                   8   4                5    2         2       6              7
5. Complete the addition – subtraction box.
                        +
                 2       4                             1     1
                 3       3                             2     3
         –       1       2                       –     1     1
   (a)           3       3             (b)             3     4
                   7                                                 1
6. A piece of wire    metre long broke into two pieces. One piece was metre
                   8                                                 4
   long. How long is the other piece?
                          9
7. Nandini’s house is       km from her school. She walked some distance and then
                         1 0
           Mathematics
    208
                    1
         took a bus forkm to reach the school. How far did she walk?
                    2
    8. Asha and Samuel have bookshelves of the same size. Asha’s
                5                                      2
         shelf is   full of books and Samuel’s shelf is full. Whose
                6                                      5
         bookshelf is more full? By what fraction?
                        1                                                        7
    9. Jaidev takes 2      minutes to walk across the school ground. Rahul takes
                        5                                                        4
         minutes to do the same. Who takes less time and by what fraction?