Answers

Add 81/21 and 70/40

1^st number: 3 18/21, 2^nd number: 1 30/40

81/21 + 70/40 is 157/28.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 21 and 40 is 840
   
   Next, find the equivalent fraction of both fractional numbers with denominator 840
2. For the 1st fraction, since 21 × 40 = 840,
   81/21 = 81 × 40/21 × 40 = 3240/840
3. Likewise, for the 2nd fraction, since 40 × 21 = 840,
   70/40 = 70 × 21/40 × 21 = 1470/840
4. Add the two like fractions:
   3240/840 + 1470/840 = 3240 + 1470/840 = 4710/840
5. 4710/840 simplified gives 157/28
6. So, 81/21 + 70/40 = 157/28
   In mixed form: 517/28

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