Answers

Add 21/15 and 54/8

1^st number: 1 6/15, 2^nd number: 6 6/8

21/15 + 54/8 is 163/20.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 15 and 8 is 120
   
   Next, find the equivalent fraction of both fractional numbers with denominator 120
2. For the 1st fraction, since 15 × 8 = 120,
   21/15 = 21 × 8/15 × 8 = 168/120
3. Likewise, for the 2nd fraction, since 8 × 15 = 120,
   54/8 = 54 × 15/8 × 15 = 810/120
4. Add the two like fractions:
   168/120 + 810/120 = 168 + 810/120 = 978/120
5. 978/120 simplified gives 163/20
6. So, 21/15 + 54/8 = 163/20
   In mixed form: 83/20

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