Answers

Add 12/42 and 9/21

12/42 + 9/21 is 5/7.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 42 and 21 is 42
   
   Next, find the equivalent fraction of both fractional numbers with denominator 42
2. For the 1st fraction, since 42 × 1 = 42,
   12/42 = 12 × 1/42 × 1 = 12/42
3. Likewise, for the 2nd fraction, since 21 × 2 = 42,
   9/21 = 9 × 2/21 × 2 = 18/42
4. Add the two like fractions:
   12/42 + 18/42 = 12 + 18/42 = 30/42
5. 30/42 simplified gives 5/7
6. So, 12/42 + 9/21 = 5/7

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