If I’m trying to find the number of unique different combinations for 8 numbers why isn’t the answer all 99999999 excluding all zero.

Question

I think the number is 40,320.

Edit: Background…For work we need to create a unique code for fraud detection and the code can be no longer than 8 numerical digits. The generation of this number is another story. This is just for my own understanding.

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Answer 1

The number of unique combinations using 8 numbers is 99999999 but I believe what you’re talking about is the number of combinations of 8 digits where each digit is used only once. And that’s why it’s less than 99999999. 12345678 is valid but 11111111 is not, 11111112 is not, etc. so you see it’s waaay less than 99999999