Subtract 3/5 from 7/21
7/21 - 3/5 is -4/15.
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,
3/5 = 3 × 21/5 × 21 = 63/105 - Subtract the two like fractions:
35/105 - 63/105 = 35 - 63/105 = -28/105 - After reducing the fraction, the answer is -4/15
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 14/21-3/5 7/21-6/5 7/42-3/5 7/21-3/10 7/21-9/5 7/63-3/5 7/21-3/15 35/21-3/5 7/21-15/5 7/21-3/25 49/21-3/5 7/21-21/5 7/21-3/35