Subtract 7/42 from 1/21
1/21 - 7/42 is -5/42.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 42 is 42
Next, find the equivalent fraction of both fractional numbers with denominator 42 - For the 1st fraction, since 21 × 2 = 42,
1/21 = 1 × 2/21 × 2 = 2/42 - Likewise, for the 2nd fraction, since 42 × 1 = 42,
7/42 = 7 × 1/42 × 1 = 7/42 - Subtract the two like fractions:
2/42 - 7/42 = 2 - 7/42 = -5/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 2/21-7/42 1/21-14/42 1/42-7/42 1/21-7/84 3/21-7/42 1/21-21/42 1/63-7/42 5/21-7/42 1/21-35/42 7/21-7/42 1/21-49/42