Answers

Subtract 80/90 from 21/50

21/50 - 80/90 is -211/450.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 50 and 90 is 450
   
   Next, find the equivalent fraction of both fractional numbers with denominator 450
2. For the 1st fraction, since 50 × 9 = 450,
   21/50 = 21 × 9/50 × 9 = 189/450
3. Likewise, for the 2nd fraction, since 90 × 5 = 450,
   80/90 = 80 × 5/90 × 5 = 400/450
4. Subtract the two like fractions:
   189/450 - 400/450 = 189 - 400/450 = -211/450

MathStep (Works offline)

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

Related: ⁴²/₅₀-⁸⁰/₉₀ ⁶³/₅₀-⁸⁰/₉₀

Subtract Fractions Calculator