How many combinations are there for a 8 digit number?

00,000,000 - 99,999,999

Since 9 is the highest single digit number if you were to make your passWord all nines then I believe that would give you the total amount of possibilities that the passWord could be.

I may be wrong but I am almost positive I am not.

If you were to try and guess a single digit passWord from 0-9 you would actually have ten different possibilities not nine because you include zero as a possibility.

So I guess the accurate answer to this question would be 100,000,000

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The above answer is very seriously wrong because the person answering does not know the difference between a combination and a permutation. In a combination, the order of the digits does not matter. Thus 123 is the same as 321.

The calculations are rather complex becuase they depend on the number of times a digit is repeated.