here are 680 three-digit numbers that are available for use as area codes in North America. As of April 2010, 301 of them were actually being used (Source: www.nanpa.com). (3 pts.)
a. How many additional three-digit codes are available for use? 379
b. Within a given area code, how many unique telephone numbers are theoretically possible?
c. As of April 2010, how many total phone numbers are possible in North America?

Question

here are 680 three-digit numbers that are available for use as area codes in North America. As of April 2010, 301 of them were actually being used (Source: www.nanpa.com). (3 pts.)
a. 	How many additional three-digit codes are available for use? 379
b. 	Within a given area code, how many unique telephone numbers are theoretically possible?
c. 	As of April 2010, how many total phone numbers are possible in North America?

turingtest · Answer

there are 1000 possible numbers because there are that many numbers from 000 through 999

within each area code is a seven-digit number, so how many can that be?

turingtest · Answer

I mean 1000 possible area codes between 000 and 999