Answers

Subtract 40/21 from 30/40

1^st number: 30/40, 2^nd number: 1 19/21

30/40 - 40/21 is -97/84.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 40 and 21 is 840
   
   Next, find the equivalent fraction of both fractional numbers with denominator 840
2. For the 1st fraction, since 40 × 21 = 840,
   30/40 = 30 × 21/40 × 21 = 630/840
3. Likewise, for the 2nd fraction, since 21 × 40 = 840,
   40/21 = 40 × 40/21 × 40 = 1600/840
4. Subtract the two like fractions:
   630/840 - 1600/840 = 630 - 1600/840 = -970/840
5. After reducing the fraction, the answer is -97/84

MathStep (Works offline)

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

Related: ⁶⁰/₄₀-⁴⁰/₂₁ ³⁰/₄₀-⁸⁰/₂₁ ³⁰/₈₀-⁴⁰/₂₁ ³⁰/₄₀-⁴⁰/₄₂ ⁹⁰/₄₀-⁴⁰/₂₁ ³⁰/₄₀-⁴⁰/₆₃

Subtract Fractions Calculator