Subtract 49/90 from 7/21
7/21 - 49/90 is -19/90.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 21 × 30 = 630,
7/21 = 7 × 30/21 × 30 = 210/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
49/90 = 49 × 7/90 × 7 = 343/630 - Subtract the two like fractions:
210/630 - 343/630 = 210 - 343/630 = -133/630 - After reducing the fraction, the answer is -19/90
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 14/21-49/90 7/21-98/90 7/42-49/90 7/63-49/90 35/21-49/90 49/21-49/90