Answers

Add 21/90 and 30/81

21/90 + 30/81 is 163/270.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 90 and 81 is 810
   
   Next, find the equivalent fraction of both fractional numbers with denominator 810
2. For the 1st fraction, since 90 × 9 = 810,
   21/90 = 21 × 9/90 × 9 = 189/810
3. Likewise, for the 2nd fraction, since 81 × 10 = 810,
   30/81 = 30 × 10/81 × 10 = 300/810
4. Add the two like fractions:
   189/810 + 300/810 = 189 + 300/810 = 489/810
5. 489/810 simplified gives 163/270
6. So, 21/90 + 30/81 = 163/270

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