Answers

Compare 8/21 and 90/40

1^st number: 8/21, 2^nd number: 2 10/40

8/21 is smaller than 90/40

Steps for comparing fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 21 and 40 is 840
2. For the 1st fraction, since 21 × 40 = 840,
   8/21 = 8 × 40/21 × 40 = 320/840
3. Likewise, for the 2nd fraction, since 40 × 21 = 840,
   90/40 = 90 × 21/40 × 21 = 1890/840
4. Since the denominators are now the same, the fraction with the bigger numerator is the greater fraction
5. 320/840 < 1890/840 or 8/21 < 90/40

MathStep (Works offline)

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

Related: ¹⁶/₂₁ and ⁹⁰/₄₀ ⁸/₄₂ and ⁹⁰/₄₀ ⁸/₂₁ and ⁹⁰/₈₀ ²⁴/₂₁ and ⁹⁰/₄₀ ⁸/₆₃ and ⁹⁰/₄₀ ⁴⁰/₂₁ and ⁹⁰/₄₀ ⁵⁶/₂₁ and ⁹⁰/₄₀

Compare Fractions Calculator