Subtract 81/80 from 15/21
1st number: 15/21, 2nd number: 1 1/80
15/21 - 81/80 is -167/560.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 80 is 1680
Next, find the equivalent fraction of both fractional numbers with denominator 1680 - For the 1st fraction, since 21 × 80 = 1680,
15/21 = 15 × 80/21 × 80 = 1200/1680 - Likewise, for the 2nd fraction, since 80 × 21 = 1680,
81/80 = 81 × 21/80 × 21 = 1701/1680 - Subtract the two like fractions:
1200/1680 - 1701/1680 = 1200 - 1701/1680 = -501/1680 - After reducing the fraction, the answer is -167/560
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/21-81/80 15/42-81/80 45/21-81/80 15/63-81/80 75/21-81/80