Answers

Subtract 2/80 from 21/42

21/42 - 2/80 is 19/40.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 42 and 80 is 1680
   
   Next, find the equivalent fraction of both fractional numbers with denominator 1680
2. For the 1st fraction, since 42 × 40 = 1680,
   21/42 = 21 × 40/42 × 40 = 840/1680
3. Likewise, for the 2nd fraction, since 80 × 21 = 1680,
   2/80 = 2 × 21/80 × 21 = 42/1680
4. Subtract the two like fractions:
   840/1680 - 42/1680 = 840 - 42/1680 = 798/1680
5. After reducing the fraction, the answer is 19/40

MathStep (Works offline)

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

Related: ²¹/₄₂-⁴/₈₀ ²¹/₈₄-²/₈₀ ⁶³/₄₂-²/₈₀ ²¹/₄₂-⁶/₈₀ ²¹/₄₂-¹⁰/₈₀ ²¹/₄₂-¹⁴/₈₀

Subtract Fractions Calculator