98,764
The greatest 4-digit number with no repeated digits is... 9876
987,654
98,764
98,764
24680 using only even numbers or 12346 which is an even number
There are 5760 such numbers.
It is 9998, or if the digits can't be repeated, it is 9876.
6*6*3 = 108 numbers.
For this kind of question, start from the left, and use the greatest possible digit for each position. Thus, in the first position you would have a 9, in the second an 8, etc.
The greatest possible number is 888... (repeating).
642
Well, numbers go on forever so I'm not sure if someone can answer that. hehe