How many 4 digit combinations are there for a group of 10 different numbers?

from 0 to 9, how many number combinations can be created if you only use groups of 4 numbers at a time?How many 4 digit combinations are there for a group of 10 different numbers?
depends whether or not you can reuse the numbers





if u can reuse the numbers:





10 x 10 x 10 x 10 = 10000





if not:





10 x 9 x 8 x 7 = 5040How many 4 digit combinations are there for a group of 10 different numbers?
they are right it is 10000





cause you so it like 10*10*10*10
10 x 9 x 8 x 7 = 5040
alot
The formula for combinations (order is not important) is:





C = n! / (n - r)! r!


n r





So, n=10 and r=4. Then n - r = 6





10 * 9 * 8 * 7 * 6! / (6!) 4!





10 * 9 * 8 * 7 / 4 * 3 * 2 * 1





= 5040 / 24 = 210





So, there are 5040 permutations (where the order is important) but only 210 combinations (e.g., 1234 is the same as 4321).
10^4 or 10000