How many four-digit numbers can you make by arranging the numbers 1 2 8 9?

Answer 1

If each of the numbers 1, 2, 8, and 9, each of which is also a digit, must be used exactly once, the answer is 4 X 3 X 2 = 24. Reasoning: Any one of the four digits may be taken first; any one of the remaining three may be taken second, and either of the remaining two may be taken next, leaving only one choice for the final digit.