Answers

Subtract 7/20 from 8/81

8/81 - 7/20 is -407/1620.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 81 and 20 is 1620
   
   Next, find the equivalent fraction of both fractional numbers with denominator 1620
2. For the 1st fraction, since 81 × 20 = 1620,
   8/81 = 8 × 20/81 × 20 = 160/1620
3. Likewise, for the 2nd fraction, since 20 × 81 = 1620,
   7/20 = 7 × 81/20 × 81 = 567/1620
4. Subtract the two like fractions:
   160/1620 - 567/1620 = 160 - 567/1620 = -407/1620

MathStep (Works offline)

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

Related: ¹⁶/₈₁-⁷/₂₀ ⁸/₈₁-¹⁴/₂₀ ⁸/₈₁-⁷/₄₀ ²⁴/₈₁-⁷/₂₀ ⁸/₈₁-²¹/₂₀ ⁸/₈₁-⁷/₆₀ ⁴⁰/₈₁-⁷/₂₀ ⁸/₈₁-³⁵/₂₀ ⁵⁶/₈₁-⁷/₂₀ ⁸/₈₁-⁴⁹/₂₀

Subtract Fractions Calculator