Answers

Add 45/21 and 72/80

1^st number: 2 3/21, 2^nd number: 72/80

45/21 + 72/80 is 213/70.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 21 and 80 is 1680
   
   Next, find the equivalent fraction of both fractional numbers with denominator 1680
2. For the 1st fraction, since 21 × 80 = 1680,
   45/21 = 45 × 80/21 × 80 = 3600/1680
3. Likewise, for the 2nd fraction, since 80 × 21 = 1680,
   72/80 = 72 × 21/80 × 21 = 1512/1680
4. Add the two like fractions:
   3600/1680 + 1512/1680 = 3600 + 1512/1680 = 5112/1680
5. 5112/1680 simplified gives 213/70
6. So, 45/21 + 72/80 = 213/70
   In mixed form: 33/70

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