Subtract 21/42 from 7/36
7/36 - 21/42 is -11/36.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 36 and 42 is 252
Next, find the equivalent fraction of both fractional numbers with denominator 252 - For the 1st fraction, since 36 × 7 = 252,
7/36 = 7 × 7/36 × 7 = 49/252 - Likewise, for the 2nd fraction, since 42 × 6 = 252,
21/42 = 21 × 6/42 × 6 = 126/252 - Subtract the two like fractions:
49/252 - 126/252 = 49 - 126/252 = -77/252 - After reducing the fraction, the answer is -11/36
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 14/36-21/42 7/72-21/42 7/36-21/84 21/36-21/42 7/36-63/42 35/36-21/42 49/36-21/42