Subtract 25/42 from 1/21
1/21 - 25/42 is -23/42.
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,
25/42 = 25 × 1/42 × 1 = 25/42 - Subtract the two like fractions:
2/42 - 25/42 = 2 - 25/42 = -23/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 2/21-25/42 1/21-50/42 1/42-25/42 1/21-25/84 3/21-25/42 1/21-75/42 1/63-25/42 5/21-25/42 7/21-25/42