Subtract 81/20 from 30/21
1st number: 1 9/21, 2nd number: 4 1/20
30/21 - 81/20 is -367/140.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 21 × 20 = 420,
30/21 = 30 × 20/21 × 20 = 600/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
81/20 = 81 × 21/20 × 21 = 1701/420 - Subtract the two like fractions:
600/420 - 1701/420 = 600 - 1701/420 = -1101/420 - After reducing the fraction, the answer is -367/140
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/21-81/20 30/42-81/20 30/21-81/40 90/21-81/20 30/63-81/20 30/21-81/60