Subtract 18/21 from 72/8
1st number: 9 0/8, 2nd number: 18/21
72/8 - 18/21 is 57/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 8 and 21 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 8 × 21 = 168,
72/8 = 72 × 21/8 × 21 = 1512/168 - Likewise, for the 2nd fraction, since 21 × 8 = 168,
18/21 = 18 × 8/21 × 8 = 144/168 - Subtract the two like fractions:
1512/168 - 144/168 = 1512 - 144/168 = 1368/168 - After reducing the fraction, the answer is 57/7
- In mixed form: 81/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 72/8-36/21 72/16-18/21 72/8-18/42 72/8-54/21 72/24-18/21 72/8-18/63 72/8-90/21 72/40-18/21 72/56-18/21