Subtract 54/72 from 21/70
21/70 - 54/72 is -9/20.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 70 and 72 is 2520
Next, find the equivalent fraction of both fractional numbers with denominator 2520 - For the 1st fraction, since 70 × 36 = 2520,
21/70 = 21 × 36/70 × 36 = 756/2520 - Likewise, for the 2nd fraction, since 72 × 35 = 2520,
54/72 = 54 × 35/72 × 35 = 1890/2520 - Subtract the two like fractions:
756/2520 - 1890/2520 = 756 - 1890/2520 = -1134/2520 - After reducing the fraction, the answer is -9/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/70-54/72 63/70-54/72