What is the prime factorization of 64?

For this we just need to keep dividing 64 until we are left with just the prime numbers:

64
=2*32
=2*2*16
=2*2*2*8
=2*2*2*2*4
=2*2*2*2*2*2

Therefore, 64 = 2^6

Start with lowest prime numbers
64/2,
2 32/2,
2 2 16/2,
2 2 2 8/2,
2 2 2 2 4/2,
2 to the 6th
check by multiplying back
2 x 2 x 2 x 2 x 2 x 2= 64

The second step on the test was the move he was supposed to