#1**+1 **

I will assume there cannot be a 0 in the first position

2 choices for first digit

3 choices for 2nd

3 choices for 3rd

3 choices for 4th

2 x 3 x 3 x 3 =....... choices

ElectricPavlov Aug 4, 2020

#2**+1 **

Let's See:

For each digit space, there can be any number, with the exception that the 1000s place cannot have a 0. We have 2 choices for the thousands place, either 1 or 3.

For the 100s place, any number is okay. 0,1, and 3 all work just fine

For the 10s place, any number can be there as well

For the 1s place, it's still 3 choices

So we have 2 choices, 3, choices, 3 choices, and 3 choices. What now? Well, we multiply our answers together, just how you would do a "clothes combination" problem. I will let you do the multiplication for yourself.

Inspirational Aug 4, 2020