Subtract 27/36 from 21/42
21/42 - 27/36 is -1/4.
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,
21/42 = 21 × 6/42 × 6 = 126/252 - Likewise, for the 2nd fraction, since 36 × 7 = 252,
27/36 = 27 × 7/36 × 7 = 189/252 - Subtract the two like fractions:
126/252 - 189/252 = 126 - 189/252 = -63/252 - After reducing the fraction, the answer is -1/4
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 21/42-54/36 21/84-27/36 21/42-27/72 63/42-27/36 21/42-81/36