Answers

Add 81/90 and 42/72

81/90 + 42/72 is 89/60.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 90 and 72 is 360
   
   Next, find the equivalent fraction of both fractional numbers with denominator 360
2. For the 1st fraction, since 90 × 4 = 360,
   81/90 = 81 × 4/90 × 4 = 324/360
3. Likewise, for the 2nd fraction, since 72 × 5 = 360,
   42/72 = 42 × 5/72 × 5 = 210/360
4. Add the two like fractions:
   324/360 + 210/360 = 324 + 210/360 = 534/360
5. 534/360 simplified gives 89/60
6. So, 81/90 + 42/72 = 89/60
   In mixed form: 129/60

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