Subtract 21/20 from 42/7
1st number: 6 0/7, 2nd number: 1 1/20
42/7 - 21/20 is 99/20.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 7 and 20 is 140
Next, find the equivalent fraction of both fractional numbers with denominator 140 - For the 1st fraction, since 7 × 20 = 140,
42/7 = 42 × 20/7 × 20 = 840/140 - Likewise, for the 2nd fraction, since 20 × 7 = 140,
21/20 = 21 × 7/20 × 7 = 147/140 - Subtract the two like fractions:
840/140 - 147/140 = 840 - 147/140 = 693/140 - After reducing the fraction, the answer is 99/20
- In mixed form: 419/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/7-21/20 42/7-42/20 42/14-21/20 42/7-21/40 42/7-63/20 42/21-21/20 42/7-21/60 42/35-21/20 42/49-21/20