Question

Each student at a certain business school is assigned a 4-digit student identification number. the first digit of the identification number cannot be zero, and the last digit of the identification number must be prime. how many different student identification numbers can the school create?

Answer 1

-prime numbers are 2, 3, 5, 7
-zero can only go in the second or third number
- so you could do 1×10, 2×10, 3×10, 4×10, 5×10, 6×10, 7×10, 8×10, and 9×10 in the second digit
- you can also do this in the third digit 5× only because you can't double a number and you still have to do your last prime numbers
-in the first digit you can only do a number once

I'm not sure what my answer is cause I'm half asleep sorry