Answers

Add 1/81 and 21/5

1^st number: 1/81, 2^nd number: 4 1/5

1/81 + 21/5 is 1706/405.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 81 and 5 is 405
   
   Next, find the equivalent fraction of both fractional numbers with denominator 405
2. For the 1st fraction, since 81 × 5 = 405,
   1/81 = 1 × 5/81 × 5 = 5/405
3. Likewise, for the 2nd fraction, since 5 × 81 = 405,
   21/5 = 21 × 81/5 × 81 = 1701/405
4. Add the two like fractions:
   5/405 + 1701/405 = 5 + 1701/405 = 1706/405
5. So, 1/81 + 21/5 = 1706/405
   In mixed form: 486/405

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