Subtract 21/7 from 42/21
1st number: 2 0/21, 2nd number: 3 0/7
42/21 - 21/7 is -1/1.
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,
42/21 = 42 × 1/21 × 1 = 42/21 - Likewise, for the 2nd fraction, since 7 × 3 = 21,
21/7 = 21 × 3/7 × 3 = 63/21 - Subtract the two like fractions:
42/21 - 63/21 = 42 - 63/21 = -21/21 - After reducing the fraction, the answer is -1/1
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/21-21/7 42/21-42/7 42/21-21/14 42/21-63/7 42/63-21/7 42/21-21/35 42/21-21/49