How many six digits even numbers are possible if the leftmost digit cannot be zero

The easiest way to do this is to write out 6 spaces like this.

_ * _ * _ * _ * _ * _ Now, in each space we need to find how many possible numbers could work.

Since the first space cannot be zero, that leaves us with 2,4,6,8 as even numbers, which is 4 even numbers.

So, we get 4*_*_*_*_*_

In all the other spaces, we CAN use 0 which means there are 5 even numbers. So, we fill in all the other spots and get:

4*5*5*5*5*5

Multiply it out and you get 12,500 different possibilities.