Subtract 3/81 from 42/21
1st number: 2 0/21, 2nd number: 3/81
42/21 - 3/81 is 53/27.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 81 is 567
Next, find the equivalent fraction of both fractional numbers with denominator 567 - For the 1st fraction, since 21 × 27 = 567,
42/21 = 42 × 27/21 × 27 = 1134/567 - Likewise, for the 2nd fraction, since 81 × 7 = 567,
3/81 = 3 × 7/81 × 7 = 21/567 - Subtract the two like fractions:
1134/567 - 21/567 = 1134 - 21/567 = 1113/567 - After reducing the fraction, the answer is 53/27
- In mixed form: 126/27
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/21-3/81 42/21-6/81 42/21-9/81 42/63-3/81 42/21-15/81 42/21-21/81