# CLASS-7SUBTRACTION OF FRACTION

Rules for Subtraction of Fraction

Step.1) Convert the mixed fraction into an improper fraction

Step.2) Convert all the fractions into like fraction

Step.3) Add the numerators of the like fractions obtained in step 2.

Step.4) Write a fraction with the numbers obtained in step 3 as the numerator and the common denominator in step 2 as the denominator.

Step.5) Reduce the fraction obtained in step 4 to its simplest form. If it is an improper fraction express it as a mixed fraction.

Numerator of the first X (LCM of denominator ÷                          denominator of the first) - Numerator of the                              second X (LCM of denominator ÷ denominator of                                       the second)

Sum of two fraction = --------------------------------------

LCM of Denominator

Example-1

7                 11

Find the Subtraction    ----------  -  -----------

30                 50

7                11

----------  -  ---------

30               50

Step.1)  First we will find the LCM of the given denominator of the given fraction.

Now, divide LCM by the denominator of the given fraction respectively

150 ÷ 30 = 5 , 150 ÷ 50 = 3

Now, multiply obtained quotient with denominator & numerator of respective fraction –

7            11

= -------- - ---------

30            50

7            7 X 5              35

-------- = -----------  =  ---------

30           30 X 5             150

11         11 X 3        33

-------- = -------- = -------

50         50 X 3       150

7          11          35         33

So, ------ - ------- = ------- - -------

30          50         150        150

35 - 33               2

= -------------  =  --------

150                150

OR

7          11          7 X (150/30)  - 11 X (150/50)

So,  ------- - -------- = -----------------------------

30          50                      150

35 - 33              2

=  -------------  =  --------        (Ans.)

150               150