Answers

Subtract 20/12 from 20/81

1^st number: 20/81, 2^nd number: 1 8/12

20/81 - 20/12 is -115/81.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 81 and 12 is 324
   
   Next, find the equivalent fraction of both fractional numbers with denominator 324
2. For the 1st fraction, since 81 × 4 = 324,
   20/81 = 20 × 4/81 × 4 = 80/324
3. Likewise, for the 2nd fraction, since 12 × 27 = 324,
   20/12 = 20 × 27/12 × 27 = 540/324
4. Subtract the two like fractions:
   80/324 - 540/324 = 80 - 540/324 = -460/324
5. After reducing the fraction, the answer is -115/81

MathStep (Works offline)

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

Related: ⁴⁰/₈₁-²⁰/₁₂ ²⁰/₈₁-⁴⁰/₁₂ ²⁰/₈₁-²⁰/₂₄ ⁶⁰/₈₁-²⁰/₁₂ ²⁰/₈₁-⁶⁰/₁₂ ²⁰/₈₁-²⁰/₃₆ ²⁰/₈₁-²⁰/₆₀ ²⁰/₈₁-²⁰/₈₄

Subtract Fractions Calculator