Question

write 256 as a product of prime factors

Answer 1

256 -> 4 -> 2 & 2
       -> 64 -> 8 & 8
8 -> 4 & 2
4 -> 2 & 2
8 -> 4 & 2
4 -> 2 & 2
(I hope this format makes sense) So you are left with 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 or $2^{8}$. I hope this helps!