Question

use fermat's little theorem to find the unit digit of 3 with 100 exponent

Answer 1

If we're using Fermat's Little theorem, the first thing we need to do is translate the question into an equation with "mod" something.

In this case, we're looking for the units digit of something, so we need to look mod 10. Thus, the equation is\[3^{100}\pmod{10}\]Make sense so far?