how many 5-digit codes if no 0's, no repeated digits

[dedwards]

how many 5 digit codes are possible if 0 cannot be used and no digit can be repeated?

10 in the first possible set so 10 x 5 = 50 50 x 50=100..im stuck

 

[galactus]

Re: help

Without 0 there are 9 choices for the first.

8 for the second.

7 for the third and so on.

Can you get it now?.

Or just think of it as choosing 5 items out of 10 where order matters. P(9,5)