Subtract 7/21 from 81/18
1st number: 4 9/18, 2nd number: 7/21
81/18 - 7/21 is 25/6.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 18 and 21 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 18 × 7 = 126,
81/18 = 81 × 7/18 × 7 = 567/126 - Likewise, for the 2nd fraction, since 21 × 6 = 126,
7/21 = 7 × 6/21 × 6 = 42/126 - Subtract the two like fractions:
567/126 - 42/126 = 567 - 42/126 = 525/126 - After reducing the fraction, the answer is 25/6
- In mixed form: 41/6
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 81/18-14/21 81/36-7/21 81/18-7/42 81/54-7/21 81/18-7/63 81/18-35/21 81/90-7/21 81/18-49/21