Answers

Subtract 21/12 from 90/72

1^st number: 1 18/72, 2^nd number: 1 9/12

90/72 - 21/12 is -1/2.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 72 and 12 is 72
   
   Next, find the equivalent fraction of both fractional numbers with denominator 72
2. For the 1st fraction, since 72 × 1 = 72,
   90/72 = 90 × 1/72 × 1 = 90/72
3. Likewise, for the 2nd fraction, since 12 × 6 = 72,
   21/12 = 21 × 6/12 × 6 = 126/72
4. Subtract the two like fractions:
   90/72 - 126/72 = 90 - 126/72 = -36/72
5. After reducing the fraction, the answer is -1/2

MathStep (Works offline)

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

Related: ⁹⁰/₇₂-⁴²/₁₂ ⁹⁰/₇₂-²¹/₂₄ ⁹⁰/₇₂-⁶³/₁₂ ⁹⁰/₇₂-²¹/₃₆ ⁹⁰/₇₂-²¹/₆₀ ⁹⁰/₇₂-²¹/₈₄

Subtract Fractions Calculator