Subtract 21/80 from 4/72
4/72 - 21/80 is -149/720.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 72 and 80 is 720
Next, find the equivalent fraction of both fractional numbers with denominator 720 - For the 1st fraction, since 72 × 10 = 720,
4/72 = 4 × 10/72 × 10 = 40/720 - Likewise, for the 2nd fraction, since 80 × 9 = 720,
21/80 = 21 × 9/80 × 9 = 189/720 - Subtract the two like fractions:
40/720 - 189/720 = 40 - 189/720 = -149/720
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 8/72-21/80 4/72-42/80 12/72-21/80 4/72-63/80 20/72-21/80 28/72-21/80