84/5 + 1 2/5 = i need tips on adding, subtracting, multiplying and dividing mixed numbers

The answer to that question is 10 wholes if im correct.

Initial question: 8 4/5 + 1 2/5 = 10 1/5

To add mixed numbers: 
If the denominators are the same for both numbers, add the numerators.
Example: 1/5 + 2/5 = 3/5

To subtract mixed numbers:
Do the same for adding but subtract.
Example: 2/5 - 1/5 = 1/5

To multiply mixed numbers:
Multiply the numerators with each other and the denominators with each other.
Example: 2/5 * 1/5 = 2/25

To divide mixed numbers:
Do the same as multiplying but divide.
Example: 2/25 ÷ 2/5 = 1/5

6(2x + 5y)6 (2x) = 12x6 (5y) = 30y12x + 30y