Answers

Subtract 20/54 from 42/81

42/81 - 20/54 is 4/27.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 81 and 54 is 162
   
   Next, find the equivalent fraction of both fractional numbers with denominator 162
2. For the 1st fraction, since 81 × 2 = 162,
   42/81 = 42 × 2/81 × 2 = 84/162
3. Likewise, for the 2nd fraction, since 54 × 3 = 162,
   20/54 = 20 × 3/54 × 3 = 60/162
4. Subtract the two like fractions:
   84/162 - 60/162 = 84 - 60/162 = 24/162
5. After reducing the fraction, the answer is 4/27

MathStep (Works offline)

Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad

Related: ⁸⁴/₈₁-²⁰/₅₄ ⁴²/₈₁-⁴⁰/₅₄ ⁴²/₈₁-⁶⁰/₅₄

Subtract Fractions Calculator