This is a question involving permutations and possibilities.Nine numbers, four slots to fill, and I'll assume no duplicates for now.
9!/(4!(9-4)!)
= 6*7*8*9 / 24
= 7*8*9 / 4
= 7*2*9
= 63*2
= 126
There are 126 unique four-digit numbers that can be arranged with the digits 1-9.
If duplicates were allowed, there would be 94possibilities, or 6,561.
how make the answer im don/now
9876 is the largest four digit number you can make if all the digits must be different.
8
Ten different digits can be used to make 10C4 = 10*9*8*7/(4*3*2*1) = 210 four-digit numbers. Either numbers starting with 0 are permitted or the 10 digits do not contain a 0.
6, as long as they are all different
how make the answer im don/now
9876 is the largest four digit number you can make if all the digits must be different.
9
8
Ten different digits can be used to make 10C4 = 10*9*8*7/(4*3*2*1) = 210 four-digit numbers. Either numbers starting with 0 are permitted or the 10 digits do not contain a 0.
6, as long as they are all different
9
First digit can be any of 3, second can be any of 3, as can third and fourth so your answer is 3 to the fourth ie 81
4! = 24 ■
3024
If you want 4-digit numbers, there are 24 of them.
55----------------------------------------------------------------------------------------------From Rafaelrz.You can make, 5! = 120, five digit numbers using 1,2,3,4 and 6.