Subtract 20/15 from 90/42
1st number: 2 6/42, 2nd number: 1 5/15
90/42 - 20/15 is 17/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 15 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 42 × 5 = 210,
90/42 = 90 × 5/42 × 5 = 450/210 - Likewise, for the 2nd fraction, since 15 × 14 = 210,
20/15 = 20 × 14/15 × 14 = 280/210 - Subtract the two like fractions:
450/210 - 280/210 = 450 - 280/210 = 170/210 - After reducing the fraction, the answer is 17/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/42-40/15 90/84-20/15 90/42-20/30 90/42-60/15 90/42-20/45 90/42-20/75