Eli5: Why is 2^9 + 2^9 = 2^10

Question

Middle school teacher here, and this is driving me crazy! Thanks!

In: 2

Answer 1

2^9 + 2^9 is 2 times 2^(9).

2 is 2^(1).

And 2^(1) times 2^(9) is 2^(10) by the usual rules of exponents.