Addition never seemed so hard

You are the commander of a star fleet and have arrived at a new planet where everything seems to be a bit.... off. Soon, in the blink of an eye, your entire fleet has been surrounded by aliens! These aliens are the inhabitants of this strange planet, and they only respect intelligent species. To prove that you and your fleet are smart enough to live, you must answer their questions:

"On our planet, addition is different than how you Earthlings add. If..."

2 $\oplus$ 3=8

3 $\oplus$ 7=27

4 $\oplus$ 5=32

5 $\oplus$ 8=60

6 $\oplus$ 7=72

Then what does "7 $\oplus$ 8" equal?

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Disclaimer: This is not an original problem, I just thought it was interesting so I decided to share it with a little alien twist...

I mean, who doesn't like aliens? :)