Subtract 27/7 from 42/21
1st number: 2 0/21, 2nd number: 3 6/7
42/21 - 27/7 is -13/7.
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,
42/21 = 42 × 1/21 × 1 = 42/21 - Likewise, for the 2nd fraction, since 7 × 3 = 21,
27/7 = 27 × 3/7 × 3 = 81/21 - Subtract the two like fractions:
42/21 - 81/21 = 42 - 81/21 = -39/21 - After reducing the fraction, the answer is -13/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/21-27/7 42/21-54/7 42/21-27/14 42/21-81/7 42/63-27/7 42/21-27/21 42/21-27/35 42/21-27/49