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.

In: 0

Answer 1

The way you find this is to ask “how many numbers can be in the first digit?”

9

Do this for all 8 digits. The math works out to 9 times 9 times 9…times 9 or 9^8

And that’s over 43,000,000. You ___ a few digits.

Your math includes all 1 2 3 4 5 6 and 7 digit numbers