Question

How many ways are there to choose a three-digit lottery number? Note that numbers like 003, 014, 222, 232 or 123 are all allowed.

Answer 1

This is the fancy permutation formula: You have n items and want to find the number of ways k items can be ordered:

P(n,k) = n!/(n-k)!

n! = n factorial = n * (n-1) * (n-2) * (n-3)... * 1

I'll let you do the calculations.