Subtract 90/21 from 42/15
1st number: 2 12/15, 2nd number: 4 6/21
42/15 - 90/21 is -52/35.
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,
90/21 = 90 × 5/21 × 5 = 450/105 - Subtract the two like fractions:
294/105 - 450/105 = 294 - 450/105 = -156/105 - After reducing the fraction, the answer is -52/35
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/15-90/21 42/30-90/21 42/15-90/42 42/45-90/21 42/15-90/63 42/75-90/21