Answers

Add 42/81 and 21/40

42/81 + 21/40 is 1127/1080.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 81 and 40 is 3240
   
   Next, find the equivalent fraction of both fractional numbers with denominator 3240
2. For the 1st fraction, since 81 × 40 = 3240,
   42/81 = 42 × 40/81 × 40 = 1680/3240
3. Likewise, for the 2nd fraction, since 40 × 81 = 3240,
   21/40 = 21 × 81/40 × 81 = 1701/3240
4. Add the two like fractions:
   1680/3240 + 1701/3240 = 1680 + 1701/3240 = 3381/3240
5. 3381/3240 simplified gives 1127/1080
6. So, 42/81 + 21/40 = 1127/1080
   In mixed form: 147/1080

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