Answers

Add 21/42 and 70/81

21/42 + 70/81 is 221/162.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 42 and 81 is 1134
   
   Next, find the equivalent fraction of both fractional numbers with denominator 1134
2. For the 1st fraction, since 42 × 27 = 1134,
   21/42 = 21 × 27/42 × 27 = 567/1134
3. Likewise, for the 2nd fraction, since 81 × 14 = 1134,
   70/81 = 70 × 14/81 × 14 = 980/1134
4. Add the two like fractions:
   567/1134 + 980/1134 = 567 + 980/1134 = 1547/1134
5. 1547/1134 simplified gives 221/162
6. So, 21/42 + 70/81 = 221/162
   In mixed form: 159/162

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