Answers

Subtract 7/81 from 18/21

18/21 - 7/81 is 437/567.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 21 and 81 is 567
   
   Next, find the equivalent fraction of both fractional numbers with denominator 567
2. For the 1st fraction, since 21 × 27 = 567,
   18/21 = 18 × 27/21 × 27 = 486/567
3. Likewise, for the 2nd fraction, since 81 × 7 = 567,
   7/81 = 7 × 7/81 × 7 = 49/567
4. Subtract the two like fractions:
   486/567 - 49/567 = 486 - 49/567 = 437/567

MathStep (Works offline)

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

Related: ³⁶/₂₁-⁷/₈₁ ¹⁸/₂₁-¹⁴/₈₁ ¹⁸/₄₂-⁷/₈₁ ⁵⁴/₂₁-⁷/₈₁ ¹⁸/₂₁-²¹/₈₁ ¹⁸/₆₃-⁷/₈₁ ⁹⁰/₂₁-⁷/₈₁ ¹⁸/₂₁-³⁵/₈₁ ¹⁸/₂₁-⁴⁹/₈₁

Subtract Fractions Calculator