Subtract 36/9 from 72/21
1st number: 3 9/21, 2nd number: 4 0/9
72/21 - 36/9 is -4/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 9 is 63
Next, find the equivalent fraction of both fractional numbers with denominator 63 - For the 1st fraction, since 21 × 3 = 63,
72/21 = 72 × 3/21 × 3 = 216/63 - Likewise, for the 2nd fraction, since 9 × 7 = 63,
36/9 = 36 × 7/9 × 7 = 252/63 - Subtract the two like fractions:
216/63 - 252/63 = 216 - 252/63 = -36/63 - After reducing the fraction, the answer is -4/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 72/21-72/9 72/42-36/9 72/21-36/18 72/63-36/9 72/21-36/27 72/21-36/45 72/21-36/63