7
7*3*4 = 84 combinations.
3 x 3 x 3 x 3 = 81 combinations
Since there are 3 numbers to choose from, there will be 2^3 = 8 combinations. This includes the null combinations which you may not wish to include in the count.
6 of them.
6 different combinations can be made with 3 items
There are 9C3 = 84 combinations.
7
The answer is 10C3 = 10*9*8/(3*2*1) = 120 combinations.
7*3*4 = 84 combinations.
3 x 3 x 3 x 3 = 81 combinations
Since there are 3 numbers to choose from, there will be 2^3 = 8 combinations. This includes the null combinations which you may not wish to include in the count.
4*3*2*1 = 24 different combinations.
6 of them.
6
6
It is called the faculty of 3 and written 3! 3! = 3 * 2 * 1 The same for 4! = 4*3*2*1 and so on...