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