Assuming positive integers, and no leading zeros, the range of five digit numbers is 10000 to 99999. The ones that end in zero can be found by taking the four digit numbers: 1000 to 9999 and multiplying each by ten. {1000,1001, 1002, ...9999}, multiplied by ten is {10000,10010,10020,....99990}. There are 9000 of them.
Chat with our AI personalities
9
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.
8*10*10=800
1,000. The list looks just like the counting numbers from 000 to 999 .
There are 10000 such codes. Each of the numbers 0-9 can be in the first position. With each such first digit, each of the numbers 0-9 can be in the second position. With each such pair of the first two digits, each of the numbers 0-9 can be in the third position. etc.