Subtract 20/72 from 20/21
20/21 - 20/72 is 85/126.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 72 is 504
Next, find the equivalent fraction of both fractional numbers with denominator 504 - For the 1st fraction, since 21 × 24 = 504,
20/21 = 20 × 24/21 × 24 = 480/504 - Likewise, for the 2nd fraction, since 72 × 7 = 504,
20/72 = 20 × 7/72 × 7 = 140/504 - Subtract the two like fractions:
480/504 - 140/504 = 480 - 140/504 = 340/504 - After reducing the fraction, the answer is 85/126
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/21-20/72 20/21-40/72 20/42-20/72 60/21-20/72 20/21-60/72 20/63-20/72