Subtract 42/36 from 21/90
1st number: 21/90, 2nd number: 1 6/36
21/90 - 42/36 is -14/15.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 36 is 180
Next, find the equivalent fraction of both fractional numbers with denominator 180 - For the 1st fraction, since 90 × 2 = 180,
21/90 = 21 × 2/90 × 2 = 42/180 - Likewise, for the 2nd fraction, since 36 × 5 = 180,
42/36 = 42 × 5/36 × 5 = 210/180 - Subtract the two like fractions:
42/180 - 210/180 = 42 - 210/180 = -168/180 - After reducing the fraction, the answer is -14/15
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/90-42/36 21/90-84/36 21/90-42/72 63/90-42/36