Subtract 1/21 from 42/15
1st number: 2 12/15, 2nd number: 1/21
42/15 - 1/21 is 289/105.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 15 and 21 is 105
Next, find the equivalent fraction of both fractional numbers with denominator 105 - For the 1st fraction, since 15 × 7 = 105,
42/15 = 42 × 7/15 × 7 = 294/105 - Likewise, for the 2nd fraction, since 21 × 5 = 105,
1/21 = 1 × 5/21 × 5 = 5/105 - Subtract the two like fractions:
294/105 - 5/105 = 294 - 5/105 = 289/105 - In mixed form: 279/105
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/15-1/21 42/15-2/21 42/30-1/21 42/15-1/42 42/15-3/21 42/45-1/21 42/15-1/63 42/15-5/21 42/75-1/21 42/15-7/21