Answers

Add 21/42 and 90/80

1^st number: 21/42, 2^nd number: 1 10/80

21/42 + 90/80 is 13/8.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 42 and 80 is 1680
   
   Next, find the equivalent fraction of both fractional numbers with denominator 1680
2. For the 1st fraction, since 42 × 40 = 1680,
   21/42 = 21 × 40/42 × 40 = 840/1680
3. Likewise, for the 2nd fraction, since 80 × 21 = 1680,
   90/80 = 90 × 21/80 × 21 = 1890/1680
4. Add the two like fractions:
   840/1680 + 1890/1680 = 840 + 1890/1680 = 2730/1680
5. 2730/1680 simplified gives 13/8
6. So, 21/42 + 90/80 = 13/8
   In mixed form: 15/8

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