Answers

Add 81/9 and 90/70

1^st number: 9 0/9, 2^nd number: 1 20/70

81/9 + 90/70 is 72/7.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 9 and 70 is 630
   
   Next, find the equivalent fraction of both fractional numbers with denominator 630
2. For the 1st fraction, since 9 × 70 = 630,
   81/9 = 81 × 70/9 × 70 = 5670/630
3. Likewise, for the 2nd fraction, since 70 × 9 = 630,
   90/70 = 90 × 9/70 × 9 = 810/630
4. Add the two like fractions:
   5670/630 + 810/630 = 5670 + 810/630 = 6480/630
5. 6480/630 simplified gives 72/7
6. So, 81/9 + 90/70 = 72/7
   In mixed form: 102/7

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