Answers

Subtract 72/40 from 20/72

1^st number: 20/72, 2^nd number: 1 32/40

20/72 - 72/40 is -137/90.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 72 and 40 is 360
   
   Next, find the equivalent fraction of both fractional numbers with denominator 360
2. For the 1st fraction, since 72 × 5 = 360,
   20/72 = 20 × 5/72 × 5 = 100/360
3. Likewise, for the 2nd fraction, since 40 × 9 = 360,
   72/40 = 72 × 9/40 × 9 = 648/360
4. Subtract the two like fractions:
   100/360 - 648/360 = 100 - 648/360 = -548/360
5. After reducing the fraction, the answer is -137/90

MathStep (Works offline)

Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad

Related: ⁴⁰/₇₂-⁷²/₄₀ ²⁰/₇₂-⁷²/₈₀ ⁶⁰/₇₂-⁷²/₄₀

Subtract Fractions Calculator