Subtract 21/49 from 7/40
7/40 - 21/49 is -71/280.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 49 is 1960
Next, find the equivalent fraction of both fractional numbers with denominator 1960 - For the 1st fraction, since 40 × 49 = 1960,
7/40 = 7 × 49/40 × 49 = 343/1960 - Likewise, for the 2nd fraction, since 49 × 40 = 1960,
21/49 = 21 × 40/49 × 40 = 840/1960 - Subtract the two like fractions:
343/1960 - 840/1960 = 343 - 840/1960 = -497/1960 - After reducing the fraction, the answer is -71/280
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 14/40-21/49 7/40-42/49 7/80-21/49 7/40-21/98 21/40-21/49 7/40-63/49 35/40-21/49 49/40-21/49