Subtract 75/90 from 15/42
15/42 - 75/90 is -10/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 42 × 15 = 630,
15/42 = 15 × 15/42 × 15 = 225/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
75/90 = 75 × 7/90 × 7 = 525/630 - Subtract the two like fractions:
225/630 - 525/630 = 225 - 525/630 = -300/630 - After reducing the fraction, the answer is -10/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/42-75/90 15/84-75/90 45/42-75/90 75/42-75/90