Answers

Add 80/21 and 28/40

1^st number: 3 17/21, 2^nd number: 28/40

80/21 + 28/40 is 947/210.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 21 and 40 is 840
   
   Next, find the equivalent fraction of both fractional numbers with denominator 840
2. For the 1st fraction, since 21 × 40 = 840,
   80/21 = 80 × 40/21 × 40 = 3200/840
3. Likewise, for the 2nd fraction, since 40 × 21 = 840,
   28/40 = 28 × 21/40 × 21 = 588/840
4. Add the two like fractions:
   3200/840 + 588/840 = 3200 + 588/840 = 3788/840
5. 3788/840 simplified gives 947/210
6. So, 80/21 + 28/40 = 947/210
   In mixed form: 4107/210

MathStep (Works offline)

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

Related: ⁸⁰/₂₁+⁵⁶/₄₀ ⁸⁰/₄₂+²⁸/₄₀ ⁸⁰/₂₁+²⁸/₈₀ ⁸⁰/₂₁+⁸⁴/₄₀ ⁸⁰/₆₃+²⁸/₄₀

Add Fractions Calculator