Subtract 21/80 from 10/42
10/42 - 21/80 is -41/1680.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 80 is 1680
Next, find the equivalent fraction of both fractional numbers with denominator 1680 - For the 1st fraction, since 42 × 40 = 1680,
10/42 = 10 × 40/42 × 40 = 400/1680 - Likewise, for the 2nd fraction, since 80 × 21 = 1680,
21/80 = 21 × 21/80 × 21 = 441/1680 - Subtract the two like fractions:
400/1680 - 441/1680 = 400 - 441/1680 = -41/1680
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 20/42-21/80 10/42-42/80 10/84-21/80 30/42-21/80 10/42-63/80 50/42-21/80 70/42-21/80