Answers

Add 72/21 and 45/90

1^st number: 3 9/21, 2^nd number: 45/90

72/21 + 45/90 is 55/14.

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,
   72/21 = 72 × 30/21 × 30 = 2160/630
3. Likewise, for the 2nd fraction, since 90 × 7 = 630,
   45/90 = 45 × 7/90 × 7 = 315/630
4. Add the two like fractions:
   2160/630 + 315/630 = 2160 + 315/630 = 2475/630
5. 2475/630 simplified gives 55/14
6. So, 72/21 + 45/90 = 55/14
   In mixed form: 313/14

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