Subtract 81/20 from 15/8
1st number: 1 7/8, 2nd number: 4 1/20
15/8 - 81/20 is -87/40.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 8 and 20 is 40
Next, find the equivalent fraction of both fractional numbers with denominator 40 - For the 1st fraction, since 8 × 5 = 40,
15/8 = 15 × 5/8 × 5 = 75/40 - Likewise, for the 2nd fraction, since 20 × 2 = 40,
81/20 = 81 × 2/20 × 2 = 162/40 - Subtract the two like fractions:
75/40 - 162/40 = 75 - 162/40 = -87/40
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/8-81/20 15/16-81/20 15/8-81/40 45/8-81/20 15/24-81/20 15/8-81/60 75/8-81/20 15/40-81/20 15/56-81/20