Subtract 21/80 from 10/40
10/40 - 21/80 is -1/80.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 80 is 80
Next, find the equivalent fraction of both fractional numbers with denominator 80 - For the 1st fraction, since 40 × 2 = 80,
10/40 = 10 × 2/40 × 2 = 20/80 - Likewise, for the 2nd fraction, since 80 × 1 = 80,
21/80 = 21 × 1/80 × 1 = 21/80 - Subtract the two like fractions:
20/80 - 21/80 = 20 - 21/80 = -1/80
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 20/40-21/80 10/40-42/80 10/80-21/80 30/40-21/80 10/40-63/80 50/40-21/80 70/40-21/80