Answer:
8 X 10^(9)
Step-by-step explanation:
Originally we have 10 digit phone numbers excluding the area code.
For each face value we have these in store: 0,1,2,3,4,5,6,7,8,9 (total 10)
But if we exclude 1 and 0 for the first digit, we are left with 8 digits.
8P1 X .......
In a phone number, digits can repeat so we can choose out of these 10 numbers freely after this.
8P1 X 10P1 X 10P1 X...
Adding the area code while assuming 10P1 is just 10...we get:
1 X 1 X 1 X 8 X 10^(9)
= 8000000000
Very interesting question, thanks for the opportunity!
