Answers

Add 70/21 and 84/90

1^st number: 3 7/21, 2^nd number: 84/90

70/21 + 84/90 is 64/15.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 21 and 90 is 630
   
   Next, find the equivalent fraction of both fractional numbers with denominator 630
2. For the 1st fraction, since 21 × 30 = 630,
   70/21 = 70 × 30/21 × 30 = 2100/630
3. Likewise, for the 2nd fraction, since 90 × 7 = 630,
   84/90 = 84 × 7/90 × 7 = 588/630
4. Add the two like fractions:
   2100/630 + 588/630 = 2100 + 588/630 = 2688/630
5. 2688/630 simplified gives 64/15
6. So, 70/21 + 84/90 = 64/15
   In mixed form: 44/15

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