Subtract 5/7 from 20/42
20/42 - 5/7 is -5/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 7 is 42
Next, find the equivalent fraction of both fractional numbers with denominator 42 - For the 1st fraction, since 42 × 1 = 42,
20/42 = 20 × 1/42 × 1 = 20/42 - Likewise, for the 2nd fraction, since 7 × 6 = 42,
5/7 = 5 × 6/7 × 6 = 30/42 - Subtract the two like fractions:
20/42 - 30/42 = 20 - 30/42 = -10/42 - After reducing the fraction, the answer is -5/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/42-5/7 20/42-10/7 20/84-5/7 20/42-5/14 60/42-5/7 20/42-15/7 20/42-5/21 20/42-25/7 20/42-5/35 20/42-35/7 20/42-5/49