Answers

Add 1/5 and 21/84

1/5 + 21/84 is 9/20.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 5 and 84 is 420
   
   Next, find the equivalent fraction of both fractional numbers with denominator 420
2. For the 1st fraction, since 5 × 84 = 420,
   1/5 = 1 × 84/5 × 84 = 84/420
3. Likewise, for the 2nd fraction, since 84 × 5 = 420,
   21/84 = 21 × 5/84 × 5 = 105/420
4. Add the two like fractions:
   84/420 + 105/420 = 84 + 105/420 = 189/420
5. 189/420 simplified gives 9/20
6. So, 1/5 + 21/84 = 9/20

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