Subtract 21/90 from 8/10
8/10 - 21/90 is 17/30.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 10 and 90 is 90
Next, find the equivalent fraction of both fractional numbers with denominator 90 - For the 1st fraction, since 10 × 9 = 90,
8/10 = 8 × 9/10 × 9 = 72/90 - Likewise, for the 2nd fraction, since 90 × 1 = 90,
21/90 = 21 × 1/90 × 1 = 21/90 - Subtract the two like fractions:
72/90 - 21/90 = 72 - 21/90 = 51/90 - After reducing the fraction, the answer is 17/30
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 16/10-21/90 8/10-42/90 8/20-21/90 24/10-21/90 8/10-63/90 8/30-21/90 40/10-21/90 8/50-21/90 56/10-21/90 8/70-21/90