Assuming you can use the values listed, and the phone number is 7 digits (e.g. XXX-XXXX), then you can select 3 numbers for the first digit (0 is exempt) then 4 selections for the rest of the digits. So, 3*4*4*4*4*4*4 = 12288 phone numbers.
10 digits are numbers in the billions.
there are 899 whole numbers that have three digits.
99999
two
California inmate ID numbers contain six digits.
10,000
Telephone numbers throughout Russia are uniformly 3 digits for the area code plus 7 digits for the local number.
Assuming you can use the values listed, and the phone number is 7 digits (e.g. XXX-XXXX), then you can select 3 numbers for the first digit (0 is exempt) then 4 selections for the rest of the digits. So, 3*4*4*4*4*4*4 = 12288 phone numbers.
10 digits are numbers in the billions.
there are 899 whole numbers that have three digits.
UK home phone numbers have 9 or 10 digits after the 0 trunk code. The digit after the 0 is a 1 or a 2.
525
There is no seconds allowed on most phones as you can input the numbers as fast you want, although the phone may have a delay catching up to the sequence of numbers that you put in.
-99
99999
two