Subtract 21/90 from 12/7
1st number: 1 5/7, 2nd number: 21/90
12/7 - 21/90 is 311/210.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 7 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 7 × 90 = 630,
12/7 = 12 × 90/7 × 90 = 1080/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
21/90 = 21 × 7/90 × 7 = 147/630 - Subtract the two like fractions:
1080/630 - 147/630 = 1080 - 147/630 = 933/630 - After reducing the fraction, the answer is 311/210
- In mixed form: 1101/210
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/7-21/90 12/7-42/90 12/14-21/90 36/7-21/90 12/7-63/90 12/21-21/90 60/7-21/90 12/35-21/90 84/7-21/90 12/49-21/90