Subtract 3/4 from 81/21
1st number: 3 18/21, 2nd number: 3/4
81/21 - 3/4 is 87/28.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 4 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 21 × 4 = 84,
81/21 = 81 × 4/21 × 4 = 324/84 - Likewise, for the 2nd fraction, since 4 × 21 = 84,
3/4 = 3 × 21/4 × 21 = 63/84 - Subtract the two like fractions:
324/84 - 63/84 = 324 - 63/84 = 261/84 - After reducing the fraction, the answer is 87/28
- In mixed form: 33/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 81/21-6/4 81/42-3/4 81/21-3/8 81/21-9/4 81/63-3/4 81/21-3/12 81/21-15/4 81/21-3/20 81/21-21/4 81/21-3/28