Answers

Add 20/21 and 72/20

1^st number: 20/21, 2^nd number: 3 12/20

20/21 + 72/20 is 478/105.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 21 and 20 is 420
   
   Next, find the equivalent fraction of both fractional numbers with denominator 420
2. For the 1st fraction, since 21 × 20 = 420,
   20/21 = 20 × 20/21 × 20 = 400/420
3. Likewise, for the 2nd fraction, since 20 × 21 = 420,
   72/20 = 72 × 21/20 × 21 = 1512/420
4. Add the two like fractions:
   400/420 + 1512/420 = 400 + 1512/420 = 1912/420
5. 1912/420 simplified gives 478/105
6. So, 20/21 + 72/20 = 478/105
   In mixed form: 458/105

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