Answers

Add 72/21 and 90/72

1^st number: 3 9/21, 2^nd number: 1 18/72

72/21 + 90/72 is 131/28.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 21 and 72 is 504
   
   Next, find the equivalent fraction of both fractional numbers with denominator 504
2. For the 1st fraction, since 21 × 24 = 504,
   72/21 = 72 × 24/21 × 24 = 1728/504
3. Likewise, for the 2nd fraction, since 72 × 7 = 504,
   90/72 = 90 × 7/72 × 7 = 630/504
4. Add the two like fractions:
   1728/504 + 630/504 = 1728 + 630/504 = 2358/504
5. 2358/504 simplified gives 131/28
6. So, 72/21 + 90/72 = 131/28
   In mixed form: 419/28

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