Question

how many 5 digit zip codes are possible? Assume all zip codes are possible

Answer 1

use combinations of 10c5- 9c4

Answer 2

There are 10 possible digits (0, 1, 2... 8, 9)
So, for each spot, there are 10 possibilities, and there are 5 spots. So, we have 10⁵ = 100000

Answer 3

there are 10 digits possible in each position of the code

so its

10 x 10 x 10 x 10 x 10

this is the fundamental theorem of counting

Answer 4

thank you... I was making it so much harder!