Subtract 20/72 from 12/42
12/42 - 20/72 is 1/126.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 72 is 504
Next, find the equivalent fraction of both fractional numbers with denominator 504 - For the 1st fraction, since 42 × 12 = 504,
12/42 = 12 × 12/42 × 12 = 144/504 - Likewise, for the 2nd fraction, since 72 × 7 = 504,
20/72 = 20 × 7/72 × 7 = 140/504 - Subtract the two like fractions:
144/504 - 140/504 = 144 - 140/504 = 4/504 - After reducing the fraction, the answer is 1/126
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/42-20/72 12/42-40/72 12/84-20/72 36/42-20/72 12/42-60/72 60/42-20/72 84/42-20/72