Answers

Add 63/4 and 20/21

1^st number: 15 3/4, 2^nd number: 20/21

63/4 + 20/21 is 1403/84.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 4 and 21 is 84
   
   Next, find the equivalent fraction of both fractional numbers with denominator 84
2. For the 1st fraction, since 4 × 21 = 84,
   63/4 = 63 × 21/4 × 21 = 1323/84
3. Likewise, for the 2nd fraction, since 21 × 4 = 84,
   20/21 = 20 × 4/21 × 4 = 80/84
4. Add the two like fractions:
   1323/84 + 80/84 = 1323 + 80/84 = 1403/84
5. So, 63/4 + 20/21 = 1403/84
   In mixed form: 1659/84

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