Answers

Add 28/21 and 72/40

1^st number: 1 7/21, 2^nd number: 1 32/40

28/21 + 72/40 is 47/15.

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,
   28/21 = 28 × 40/21 × 40 = 1120/840
3. Likewise, for the 2nd fraction, since 40 × 21 = 840,
   72/40 = 72 × 21/40 × 21 = 1512/840
4. Add the two like fractions:
   1120/840 + 1512/840 = 1120 + 1512/840 = 2632/840
5. 2632/840 simplified gives 47/15
6. So, 28/21 + 72/40 = 47/15
   In mixed form: 32/15

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