Answers

Add 8/40 and 81/21

1^st number: 8/40, 2^nd number: 3 18/21

8/40 + 81/21 is 142/35.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 40 and 21 is 840
   
   Next, find the equivalent fraction of both fractional numbers with denominator 840
2. For the 1st fraction, since 40 × 21 = 840,
   8/40 = 8 × 21/40 × 21 = 168/840
3. Likewise, for the 2nd fraction, since 21 × 40 = 840,
   81/21 = 81 × 40/21 × 40 = 3240/840
4. Add the two like fractions:
   168/840 + 3240/840 = 168 + 3240/840 = 3408/840
5. 3408/840 simplified gives 142/35
6. So, 8/40 + 81/21 = 142/35
   In mixed form: 42/35

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