Answers

Subtract 21/20 from 50/90

1^st number: 50/90, 2^nd number: 1 1/20

50/90 - 21/20 is -89/180.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 90 and 20 is 180
   
   Next, find the equivalent fraction of both fractional numbers with denominator 180
2. For the 1st fraction, since 90 × 2 = 180,
   50/90 = 50 × 2/90 × 2 = 100/180
3. Likewise, for the 2nd fraction, since 20 × 9 = 180,
   21/20 = 21 × 9/20 × 9 = 189/180
4. Subtract the two like fractions:
   100/180 - 189/180 = 100 - 189/180 = -89/180

MathStep (Works offline)

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

Related: ⁵⁰/₉₀-⁴²/₂₀ ⁵⁰/₉₀-²¹/₄₀ ⁵⁰/₉₀-⁶³/₂₀ ⁵⁰/₉₀-²¹/₆₀

Subtract Fractions Calculator