There can be 103 = 1000 codes.
If you include 0000, ten thousand unique four digit codes are possible.
As far as I can tell, all 5 digit numbers are potential zip codes, so there are 99999 + 1 potential zip codes, or 100,000. Many of these are not actually is use.
10*9*8*7*6=30,240
There are 900 possible three-digit numbers not beginning with 0. (Note, however, that this question does not accurately describe the restrictions on numbers that can be used as area codes.)
yes of course I know people with 3 and 2 digit addresses
There are 210 4 digit combinations and 5040 different 4 digit codes.
If you include 0000, ten thousand unique four digit codes are possible.
As far as I can tell, all 5 digit numbers are potential zip codes, so there are 99999 + 1 potential zip codes, or 100,000. Many of these are not actually is use.
10*9*8*7*6=30,240
There are 900 possible three-digit numbers not beginning with 0. (Note, however, that this question does not accurately describe the restrictions on numbers that can be used as area codes.)
yes of course I know people with 3 and 2 digit addresses
3x10x10x10x9=2700
If the first digit can be zero, there are 5,040. If the first digit can't be zero, there are only 4,536.
There are 26 choices for the first letter, 25 choices for the second letter (since we can't repeat the first letter), and 10 choices for the digit. Therefore, the total number of possible codes is: 26 x 25 x 10 = 6,500 So there are 6,500 possible codes with 2 letters and one digit if no letter or digit appears more than once.
5
10 x 9 x 8 = 720 different "permutations"
10!/(10-6)! =10!/4! = 10*9*8*7*6*5 = 151200 different codes