Subtract 18/72 from 21/80
21/80 - 18/72 is 1/80.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 80 and 72 is 720
Next, find the equivalent fraction of both fractional numbers with denominator 720 - For the 1st fraction, since 80 × 9 = 720,
21/80 = 21 × 9/80 × 9 = 189/720 - Likewise, for the 2nd fraction, since 72 × 10 = 720,
18/72 = 18 × 10/72 × 10 = 180/720 - Subtract the two like fractions:
189/720 - 180/720 = 189 - 180/720 = 9/720 - After reducing the fraction, the answer is 1/80
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/80-18/72 21/80-36/72 63/80-18/72 21/80-54/72 21/80-90/72