How many possible calls can a telemarketer make by dialing a seven digit phone number with an area code?

Question

This is for our permutations and combinations unit. 

Answer 1

With one area code, the HATED telemarketer could theoretically make 8 million different calls, because the first digit of a 7-digit number cannot be either 1 or 0.

 

You'd have to find out how many area codes there are in North America, if you wanted to expand the telemarketer's obnoxious activity.