Answers

Add 90/81 and 42/40

1^st number: 1 9/81, 2^nd number: 1 2/40

90/81 + 42/40 is 389/180.

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,
   90/81 = 90 × 40/81 × 40 = 3600/3240
3. Likewise, for the 2nd fraction, since 40 × 81 = 3240,
   42/40 = 42 × 81/40 × 81 = 3402/3240
4. Add the two like fractions:
   3600/3240 + 3402/3240 = 3600 + 3402/3240 = 7002/3240
5. 7002/3240 simplified gives 389/180
6. So, 90/81 + 42/40 = 389/180
   In mixed form: 229/180

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