Answers

Add 81/21 and 1/15

1^st number: 3 18/21, 2^nd number: 1/15

81/21 + 1/15 is 412/105.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 21 and 15 is 105
   
   Next, find the equivalent fraction of both fractional numbers with denominator 105
2. For the 1st fraction, since 21 × 5 = 105,
   81/21 = 81 × 5/21 × 5 = 405/105
3. Likewise, for the 2nd fraction, since 15 × 7 = 105,
   1/15 = 1 × 7/15 × 7 = 7/105
4. Add the two like fractions:
   405/105 + 7/105 = 405 + 7/105 = 412/105
5. So, 81/21 + 1/15 = 412/105
   In mixed form: 397/105

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