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