Answers

Add 42/21 and 30/90

1^st number: 2 0/21, 2^nd number: 30/90

42/21 + 30/90 is 7/3.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 21 and 90 is 630
   
   Next, find the equivalent fraction of both fractional numbers with denominator 630
2. For the 1st fraction, since 21 × 30 = 630,
   42/21 = 42 × 30/21 × 30 = 1260/630
3. Likewise, for the 2nd fraction, since 90 × 7 = 630,
   30/90 = 30 × 7/90 × 7 = 210/630
4. Add the two like fractions:
   1260/630 + 210/630 = 1260 + 210/630 = 1470/630
5. 1470/630 simplified gives 7/3
6. So, 42/21 + 30/90 = 7/3
   In mixed form: 21/3

MathStep (Works offline)

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

Related: ⁸⁴/₂₁+³⁰/₉₀ ⁴²/₂₁+⁶⁰/₉₀ ⁴²/₆₃+³⁰/₉₀

Add Fractions Calculator