Subtract 3/10 from 21/90
21/90 - 3/10 is -1/15.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 10 is 90
Next, find the equivalent fraction of both fractional numbers with denominator 90 - For the 1st fraction, since 90 × 1 = 90,
21/90 = 21 × 1/90 × 1 = 21/90 - Likewise, for the 2nd fraction, since 10 × 9 = 90,
3/10 = 3 × 9/10 × 9 = 27/90 - Subtract the two like fractions:
21/90 - 27/90 = 21 - 27/90 = -6/90 - After reducing the fraction, the answer is -1/15
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/90-3/10 21/90-6/10 21/90-3/20 63/90-3/10 21/90-9/10 21/90-3/30 21/90-15/10 21/90-3/50 21/90-21/10 21/90-3/70