2240
In base ten, there are 9000 four digit number, the numbers are from 1000 to 9999. If you allow leading zeros, then there are 10000 numbers. [0000 - 9999]
1234
128
Assuming that the first digit of the 4 digit number cannot be 0, then there are 9 possible digits for the first of the four. Also assuming that each digit does not need to be unique, then the next three digits of the four can have 10 possible for each. That results in 9x10x10x10 = 9000 possible 4 digit numbers. If, however, you can not use the same number twice in completing the 4 digit number, and the first digit cannot be 0, then the result is 9x9x8x7 = 4536 possible 4 digit numbers. If the 4 digit number can start with 0, then there are 10,000 possible 4 digit numbers. If the 4 digit number can start with 0, and you cannot use any number twice, then the result is 10x9x8x7 = 5040 possilbe 4 digit numbers.
7000 - 999 ie 6001 four digit numbers
900 numbers
There are 12 such numbers.
9,000
90
2240
There are 7200 such numbers.
625 if numbers can have leading 0s, 500 otherwise.
67 of them.
500 or so.
The numbers from 1000 to 9999 are all 4 digits, as are -1000 to -9999. Therefore there are 18,000 four-digit numbers in all.
The numbers from 1000 to 9999 are all 4 digits, as are -1000 to -9999. Therefore there are 18,000 four-digit numbers in all.