Subtract 20/7 from 15/21
1st number: 15/21, 2nd number: 2 6/7
15/21 - 20/7 is -15/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 7 is 21
Next, find the equivalent fraction of both fractional numbers with denominator 21 - For the 1st fraction, since 21 × 1 = 21,
15/21 = 15 × 1/21 × 1 = 15/21 - Likewise, for the 2nd fraction, since 7 × 3 = 21,
20/7 = 20 × 3/7 × 3 = 60/21 - Subtract the two like fractions:
15/21 - 60/21 = 15 - 60/21 = -45/21 - After reducing the fraction, the answer is -15/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/21-20/7 15/21-40/7 15/42-20/7 15/21-20/14 45/21-20/7 15/21-60/7 15/63-20/7 15/21-20/21 75/21-20/7 15/21-20/35 15/21-20/49