Answers

Add 21/42 and 2/5

21/42 + 2/5 is 9/10.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 42 and 5 is 210
   
   Next, find the equivalent fraction of both fractional numbers with denominator 210
2. For the 1st fraction, since 42 × 5 = 210,
   21/42 = 21 × 5/42 × 5 = 105/210
3. Likewise, for the 2nd fraction, since 5 × 42 = 210,
   2/5 = 2 × 42/5 × 42 = 84/210
4. Add the two like fractions:
   105/210 + 84/210 = 105 + 84/210 = 189/210
5. 189/210 simplified gives 9/10
6. So, 21/42 + 2/5 = 9/10

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