Subtract 7/20 from 72/21
1st number: 3 9/21, 2nd number: 7/20
72/21 - 7/20 is 431/140.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 21 × 20 = 420,
72/21 = 72 × 20/21 × 20 = 1440/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
7/20 = 7 × 21/20 × 21 = 147/420 - Subtract the two like fractions:
1440/420 - 147/420 = 1440 - 147/420 = 1293/420 - After reducing the fraction, the answer is 431/140
- In mixed form: 311/140
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 72/21-14/20 72/42-7/20 72/21-7/40 72/21-21/20 72/63-7/20 72/21-7/60 72/21-35/20 72/21-49/20