Answers

Add 15/21 and 70/40

1^st number: 15/21, 2^nd number: 1 30/40

15/21 + 70/40 is 69/28.

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,
   15/21 = 15 × 40/21 × 40 = 600/840
3. Likewise, for the 2nd fraction, since 40 × 21 = 840,
   70/40 = 70 × 21/40 × 21 = 1470/840
4. Add the two like fractions:
   600/840 + 1470/840 = 600 + 1470/840 = 2070/840
5. 2070/840 simplified gives 69/28
6. So, 15/21 + 70/40 = 69/28
   In mixed form: 213/28

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