How many different 3 digit numbers can be formed

[Guest]

How many different 3 digit numbers can be formed from the digits 0,1,2,3,4,5, if digits CAN be repeated?

Wouldn't u do: 6^3= 216, if they can be repeated

cuz another questions was like: How many ways can we assign an 8-letter name to a computer file if we use the letters from A to Z with repetition, and the answer was 26^8

I dont understand why the answers wouldn't be the same, cuz 216 is not the right answer.

 

[mark07]

012 is considered 12 and is not a 3-digit number, right?

You can not start with zero.

5*6*6 would be the right answer.

 

[Count Iblis]

How many different 3 digit numbers can be formed from the digits 0,1,2,3,4,5, if digits CAN be repeated?

Wouldn't u do: 6^3= 216, if they can be repeated

cuz another questions was like: How many ways can we assign an 8-letter name to a computer file if we use the letters from A to Z with repetition, and the answer was 26^8

I dont understand why the answers wouldn't be the same, cuz 216 is not the right answer.

The 6^3 number combinations contain some unwanted things, like 000, 001, 010 etc. If we demand that a number cannot start with a zero, then for the first digit you have five choices and for the other two you have six choices. There are then 5*6^2 = 180 possible numbers.