How do you get the same base for the power

You use division

over 2 or 4 or 3 or 5 or 7 and so on
in this case 2 is good

64 = 2 * 2 * 2 * 2 * 2 * 2 ( use division) = 2^6

16 = 2 * 2 * 2 * 2 = 2^4

number reminder
64 0
32 0
16 0
8    0
4   0
2   0
1   1

so 64 = 2^6 (number of zeros) no reminder

(-8,5) bu tun not sure ok