Subtract 20/21 from 5/42
5/42 - 20/21 is -5/6.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 21 is 42
Next, find the equivalent fraction of both fractional numbers with denominator 42 - For the 1st fraction, since 42 × 1 = 42,
5/42 = 5 × 1/42 × 1 = 5/42 - Likewise, for the 2nd fraction, since 21 × 2 = 42,
20/21 = 20 × 2/21 × 2 = 40/42 - Subtract the two like fractions:
5/42 - 40/42 = 5 - 40/42 = -35/42 - After reducing the fraction, the answer is -5/6
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 10/42-20/21 5/42-40/21 5/84-20/21 5/42-20/42 15/42-20/21 5/42-60/21 5/42-20/63 25/42-20/21 35/42-20/21