Answers

Subtract 20/21 from 15/36

15/36 - 20/21 is -15/28.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 36 and 21 is 252
   
   Next, find the equivalent fraction of both fractional numbers with denominator 252
2. For the 1st fraction, since 36 × 7 = 252,
   15/36 = 15 × 7/36 × 7 = 105/252
3. Likewise, for the 2nd fraction, since 21 × 12 = 252,
   20/21 = 20 × 12/21 × 12 = 240/252
4. Subtract the two like fractions:
   105/252 - 240/252 = 105 - 240/252 = -135/252
5. After reducing the fraction, the answer is -15/28

MathStep (Works offline)

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

Related: ³⁰/₃₆-²⁰/₂₁ ¹⁵/₃₆-⁴⁰/₂₁ ¹⁵/₇₂-²⁰/₂₁ ¹⁵/₃₆-²⁰/₄₂ ⁴⁵/₃₆-²⁰/₂₁ ¹⁵/₃₆-⁶⁰/₂₁ ¹⁵/₃₆-²⁰/₆₃ ⁷⁵/₃₆-²⁰/₂₁

Subtract Fractions Calculator