Answers

Add 81/18 and 54/21

1^st number: 4 9/18, 2^nd number: 2 12/21

81/18 + 54/21 is 99/14.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 18 and 21 is 126
   
   Next, find the equivalent fraction of both fractional numbers with denominator 126
2. For the 1st fraction, since 18 × 7 = 126,
   81/18 = 81 × 7/18 × 7 = 567/126
3. Likewise, for the 2nd fraction, since 21 × 6 = 126,
   54/21 = 54 × 6/21 × 6 = 324/126
4. Add the two like fractions:
   567/126 + 324/126 = 567 + 324/126 = 891/126
5. 891/126 simplified gives 99/14
6. So, 81/18 + 54/21 = 99/14
   In mixed form: 71/14

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