Answers

Add 3/18 and 21/42

3/18 + 21/42 is 2/3.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 18 and 42 is 126
   
   Next, find the equivalent fraction of both fractional numbers with denominator 126
2. For the 1st fraction, since 18 × 7 = 126,
   3/18 = 3 × 7/18 × 7 = 21/126
3. Likewise, for the 2nd fraction, since 42 × 3 = 126,
   21/42 = 21 × 3/42 × 3 = 63/126
4. Add the two like fractions:
   21/126 + 63/126 = 21 + 63/126 = 84/126
5. 84/126 simplified gives 2/3
6. So, 3/18 + 21/42 = 2/3

MathStep (Works offline)

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

Related: ⁶/₁₈+²¹/₄₂ ³/₃₆+²¹/₄₂ ³/₁₈+²¹/₈₄ ⁹/₁₈+²¹/₄₂ ³/₁₈+⁶³/₄₂ ³/₅₄+²¹/₄₂ ¹⁵/₁₈+²¹/₄₂ ³/₉₀+²¹/₄₂ ²¹/₁₈+²¹/₄₂

Add Fractions Calculator