Answers

Add 21/45 and 28/90

21/45 + 28/90 is 7/9.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 45 and 90 is 90
   
   Next, find the equivalent fraction of both fractional numbers with denominator 90
2. For the 1st fraction, since 45 × 2 = 90,
   21/45 = 21 × 2/45 × 2 = 42/90
3. Likewise, for the 2nd fraction, since 90 × 1 = 90,
   28/90 = 28 × 1/90 × 1 = 28/90
4. Add the two like fractions:
   42/90 + 28/90 = 42 + 28/90 = 70/90
5. 70/90 simplified gives 7/9
6. So, 21/45 + 28/90 = 7/9

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