Mathematical Puzzle : I to myself and over me chase the next , together does the work

If,
1 + 2 = 3
2 + 3 = 10
5 + 4 = 45
7 + 6 = 91

Then what is

9 + 7 =???

Hint: I to myself and over me chase the next , together does the work

—————- Hint to solution

its simeple : lets take 9+7=?
I to myself => 9X9
Over me chase the next =? 9X7
together does the work =? 81 + 63=144

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