Answers

Add 21/90 and 45/12

1^st number: 21/90, 2^nd number: 3 9/12

21/90 + 45/12 is 239/60.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 90 and 12 is 180
   
   Next, find the equivalent fraction of both fractional numbers with denominator 180
2. For the 1st fraction, since 90 × 2 = 180,
   21/90 = 21 × 2/90 × 2 = 42/180
3. Likewise, for the 2nd fraction, since 12 × 15 = 180,
   45/12 = 45 × 15/12 × 15 = 675/180
4. Add the two like fractions:
   42/180 + 675/180 = 42 + 675/180 = 717/180
5. 717/180 simplified gives 239/60
6. So, 21/90 + 45/12 = 239/60
   In mixed form: 359/60

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