Answers

Subtract 5/21 from 12/81

12/81 - 5/21 is -17/189.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 81 and 21 is 567
   
   Next, find the equivalent fraction of both fractional numbers with denominator 567
2. For the 1st fraction, since 81 × 7 = 567,
   12/81 = 12 × 7/81 × 7 = 84/567
3. Likewise, for the 2nd fraction, since 21 × 27 = 567,
   5/21 = 5 × 27/21 × 27 = 135/567
4. Subtract the two like fractions:
   84/567 - 135/567 = 84 - 135/567 = -51/567
5. After reducing the fraction, the answer is -17/189

MathStep (Works offline)

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

Related: ²⁴/₈₁-⁵/₂₁ ¹²/₈₁-¹⁰/₂₁ ¹²/₈₁-⁵/₄₂ ³⁶/₈₁-⁵/₂₁ ¹²/₈₁-¹⁵/₂₁ ¹²/₈₁-⁵/₆₃ ⁶⁰/₈₁-⁵/₂₁ ¹²/₈₁-²⁵/₂₁ ⁸⁴/₈₁-⁵/₂₁ ¹²/₈₁-³⁵/₂₁

Subtract Fractions Calculator