How many positive 3-digit integers can be formed using the digits 0, 1, 2, 3, 4, and 5?

Question

My Question says, Using the digits (0, 1, 2, 3, 4, 5), how many positive 3-digit integers can be formed?

So my work so far is for positive 3 digit integers you would have the choice of 6 digits for the first digit, the choice of 6 digits for the second digit, and the choice of 6 digits for the third digit: (6)(6)(6)

But I'm not sure where to go from here, do I simply multiply them together? Is there another step afterwards? Am I missing something? Please help!

Answer 1

The first digit cannot be $0$. Therefore the answer is $5\times6^2$.