Subtract 21/90 from 8/12
8/12 - 21/90 is 13/30.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 12 and 90 is 180
Next, find the equivalent fraction of both fractional numbers with denominator 180 - For the 1st fraction, since 12 × 15 = 180,
8/12 = 8 × 15/12 × 15 = 120/180 - Likewise, for the 2nd fraction, since 90 × 2 = 180,
21/90 = 21 × 2/90 × 2 = 42/180 - Subtract the two like fractions:
120/180 - 42/180 = 120 - 42/180 = 78/180 - After reducing the fraction, the answer is 13/30
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 16/12-21/90 8/12-42/90 8/24-21/90 24/12-21/90 8/12-63/90 8/36-21/90 40/12-21/90 8/60-21/90 56/12-21/90 8/84-21/90