Subtract 90/5 from 7/21
1st number: 7/21, 2nd number: 18 0/5
7/21 - 90/5 is -53/3.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 5 is 105
Next, find the equivalent fraction of both fractional numbers with denominator 105 - For the 1st fraction, since 21 × 5 = 105,
7/21 = 7 × 5/21 × 5 = 35/105 - Likewise, for the 2nd fraction, since 5 × 21 = 105,
90/5 = 90 × 21/5 × 21 = 1890/105 - Subtract the two like fractions:
35/105 - 1890/105 = 35 - 1890/105 = -1855/105 - After reducing the fraction, the answer is -53/3
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 14/21-90/5 7/42-90/5 7/21-90/10 7/63-90/5 7/21-90/15 35/21-90/5 7/21-90/25 49/21-90/5 7/21-90/35