Thursday

December 18, 2014

December 18, 2014

Posted by **angela** on Thursday, May 13, 2010 at 8:11pm.

- math -
**Damon**, Thursday, May 13, 2010 at 8:23pmI assume 0 through 9 are allowed and repeats are possible. For example 000-0000 is allowed.

How many prefixes?

10*10*10 = 1,000

how many digits

10*10*10*10 = 10,000

so 10^3 * 10^4 = 10^7 = 10 million

I guess that is why they needed area codes.

**Answer this Question**

**Related Questions**

Math. Explain - From the digits 1, 2, 3, and 4, how many positive integers are ...

6 th grade Math - You can find the total number of different 4-digit numbers of ...

computer programming - Write a program that simulates the dial of a phone number...

MATH Trouble - I have no idea what this problem means: For how many two-digit ...

math - use the clues to find the 7th digit mystery number. * Its is between 1 ...

Math - 1.) A security code has seven characters. Each code begins with two ...

4th grade math - Find the mystery number. It is a 4 digit odd number. All the ...

Math (Reiny) - Regarding my question below, when the question talks about digits...

math - find the mystery number, it is a 4 digit odd number, all the digits are ...

Math - i am a four digit number. all of my digits are different. my first digit ...