9 C 5 = 126
If the order doesn't matter, it is a combination.
If the order does matter, it is a permutation.
TI-84
.
24
27 three digit numbers from the digits 3, 5, 7 including repetitions.
Five numbers (5, 6, 7, 8, 9) can be selected for each of the 5 digits. So, there are 5*5*5*5*5 or 55 or 3125 five digit numbers.
Oh, dude, let me break it down for you. So, you've got 5 digits to choose from for the hundreds place, then 4 left for the tens place after you've used one for the hundreds, and finally 3 left for the units place after using 2 for the hundreds and tens. Multiply those together and you get 60 possible 3-digit numbers. Easy peasy, lemon squeezy!
24
24
500
1 set
It is 120 if the digits cannot be repeated.
5040 different 4 digit numbers can be formed with the digits 123456789. This is assuming that no digits are repeated with each combination.
3x3x3=27
6*6*3 = 108 numbers.
36
4*3*2*1 = 24
6*5*4*3*2*1=720 possible numbers
48 of them if digits may not be repeated. 100 if they can.
There are 5! = 120 such numbers.