Hey guys, I need some help with my descrete math homework.
The question is...
How many integers between 1500 and 8000 (inclusive) contain no repeated digits?
Now, I know its possible to go through and count each one, but the answer is not the point. I need to figure out how it is done. There is a trick of some kind that I am finding difficult to pinpoint. Any help would be very appreciated.
Also, I guess some background may be helpful. We are in the middle of a shallow study of combinatorics. This includes combinations and permeatations. I just cant figure out how in the world this can be done simplisticly... Thanks!
The question is...
How many integers between 1500 and 8000 (inclusive) contain no repeated digits?
Now, I know its possible to go through and count each one, but the answer is not the point. I need to figure out how it is done. There is a trick of some kind that I am finding difficult to pinpoint. Any help would be very appreciated.
Also, I guess some background may be helpful. We are in the middle of a shallow study of combinatorics. This includes combinations and permeatations. I just cant figure out how in the world this can be done simplisticly... Thanks!