what is the ones digit if 9^55 is expressed as an integer?

Question

what is the ones digit if 9^55 is expressed as an integer? my calculator doesn't go that far

Answer 1

It does not need to.

9^0 = 1
9^1 = 9
9^2 = 81
9^3 = 729
9^4 = 6561

A trend.

when 9 is raised to an even power, the result ends with a 1.
when 9 is raised to an odd power, the result ends with a 9.