Answers

Add 81/72 and 21/20

1^st number: 1 9/72, 2^nd number: 1 1/20

81/72 + 21/20 is 87/40.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 72 and 20 is 360
   
   Next, find the equivalent fraction of both fractional numbers with denominator 360
2. For the 1st fraction, since 72 × 5 = 360,
   81/72 = 81 × 5/72 × 5 = 405/360
3. Likewise, for the 2nd fraction, since 20 × 18 = 360,
   21/20 = 21 × 18/20 × 18 = 378/360
4. Add the two like fractions:
   405/360 + 378/360 = 405 + 378/360 = 783/360
5. 783/360 simplified gives 87/40
6. So, 81/72 + 21/20 = 87/40
   In mixed form: 27/40

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