Help me to understand why this value converts to that value

I am struggling using the Mahattan Quant guides to understand an exponent question.

Why does 6^60+6^60+6^60=6^61?
At first I thought 6^180 but I'm not multiplying so that rule doesn't apply.
Then I thought 6^60(1+1+1) but that doesn't make sense.
So what rule am I missing that makes 6^60+6^60+6^60=6^61?

Thanks