Subtract 90/9 from 7/21
1st number: 7/21, 2nd number: 10 0/9
7/21 - 90/9 is -29/3.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 9 is 63
Next, find the equivalent fraction of both fractional numbers with denominator 63 - For the 1st fraction, since 21 × 3 = 63,
7/21 = 7 × 3/21 × 3 = 21/63 - Likewise, for the 2nd fraction, since 9 × 7 = 63,
90/9 = 90 × 7/9 × 7 = 630/63 - Subtract the two like fractions:
21/63 - 630/63 = 21 - 630/63 = -609/63 - After reducing the fraction, the answer is -29/3
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 14/21-90/9 7/42-90/9 7/21-90/18 7/63-90/9 7/21-90/27 35/21-90/9 7/21-90/45 49/21-90/9 7/21-90/63