CLASS-4
SUBTRACTION OF FRACTION

Step.1 - first find LCM of ‘Denominators’ 20 & 30. 

 LCM = 5 x 2 x 2 x 3 = 60,

So, LCM of 20 & 30 = 60, put 60 as ‘Denominator’ at next step.

Step.2 – Divide by denominator of 1^st fraction to LCM, after getting the quotient from this divide, multiply it’s ‘Numerator’ & earlier obtained quotient. 60 ÷ 20 = 3 ; 5 X 3 = 15.  So, 15 is new ‘Numerator’ of 1^st fraction

Step.3 – Divide by denominator of 2^nd fraction to LCM, after getting the quotient from this divide, multiply it’s ‘Numerator’ & earlier obtained quotient. 60 ÷ 30 = 2 ; 4 X 2 = 8. So, 8 is the new ‘Numerator’ of 2^nd fraction 

Step.4 – Now, subtract two new ‘Numerators’ obtained from two separate Fraction. 15 - 8 = 7 is new ‘Numerator’ . 

 So, the answer is  7/60.