Answers

Subtract 21/16 from 15/81

1^st number: 15/81, 2^nd number: 1 5/16

15/81 - 21/16 is -487/432.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 81 and 16 is 1296
   
   Next, find the equivalent fraction of both fractional numbers with denominator 1296
2. For the 1st fraction, since 81 × 16 = 1296,
   15/81 = 15 × 16/81 × 16 = 240/1296
3. Likewise, for the 2nd fraction, since 16 × 81 = 1296,
   21/16 = 21 × 81/16 × 81 = 1701/1296
4. Subtract the two like fractions:
   240/1296 - 1701/1296 = 240 - 1701/1296 = -1461/1296
5. After reducing the fraction, the answer is -487/432

MathStep (Works offline)

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

Related: ³⁰/₈₁-²¹/₁₆ ¹⁵/₈₁-⁴²/₁₆ ¹⁵/₈₁-²¹/₃₂ ⁴⁵/₈₁-²¹/₁₆ ¹⁵/₈₁-⁶³/₁₆ ¹⁵/₈₁-²¹/₄₈ ⁷⁵/₈₁-²¹/₁₆ ¹⁵/₈₁-²¹/₈₀

Subtract Fractions Calculator