CLASS-7
SUBTRACTION 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