Answers

Subtract 42/80 from 20/70

20/70 - 42/80 is -67/280.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 70 and 80 is 560
   
   Next, find the equivalent fraction of both fractional numbers with denominator 560
2. For the 1st fraction, since 70 × 8 = 560,
   20/70 = 20 × 8/70 × 8 = 160/560
3. Likewise, for the 2nd fraction, since 80 × 7 = 560,
   42/80 = 42 × 7/80 × 7 = 294/560
4. Subtract the two like fractions:
   160/560 - 294/560 = 160 - 294/560 = -134/560
5. After reducing the fraction, the answer is -67/280

MathStep (Works offline)

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

Related: ⁴⁰/₇₀-⁴²/₈₀ ²⁰/₇₀-⁸⁴/₈₀ ⁶⁰/₇₀-⁴²/₈₀

Subtract Fractions Calculator