Subtract 90/36 from 20/42
1st number: 20/42, 2nd number: 2 18/36
20/42 - 90/36 is -85/42.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 36 is 252
Next, find the equivalent fraction of both fractional numbers with denominator 252 - For the 1st fraction, since 42 × 6 = 252,
20/42 = 20 × 6/42 × 6 = 120/252 - Likewise, for the 2nd fraction, since 36 × 7 = 252,
90/36 = 90 × 7/36 × 7 = 630/252 - Subtract the two like fractions:
120/252 - 630/252 = 120 - 630/252 = -510/252 - After reducing the fraction, the answer is -85/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/42-90/36 20/84-90/36 20/42-90/72 60/42-90/36