I’m embarrased that I don’t remember how to do this, but alas, my mind is not pulling it out right now.
I have a string of 3 characters. Each character can be 0-9 A-Z (caps only)
How many combinations are there?
I was thinking
36X36X36 = 46656. However, I can’t remember if this is correct.
Assuming you don’t mind repeating characters (Like CCC), you are quite correct. If you don’t want any character repeated then it would be 36x35x34, or 42,840. The way to think it through is to ask, “How choices can I have in for the first spot?” (26 letters plus 10 digits, 36) then “How many in the second spot?” (Still 36 if you don’t mind repeats, 35 if you do) and finally, how many in the third spot (36 or, you guessed it, 34, depending). Multiply to find the total number of combinations.
DD
Yeah, that’s right as long as the order of the digits matters. If it doesn’t (that is, if M4F means the same thing as 4FM), it’s a bit different, but I don’t remember how to figure it out.
You divide the result (42,840) by 3! to factor out the number of ways of arranging three objects. (Answer: 7140.)
When my sixth grade math teacher wrote “6!” on the blackboard, and asked if anyone knew what that meant, I raised my hand and shouted, “SIX!!!.”