Question: how many combinations of 6 variables?
Answer: It's the same as possibilities to a 6 digit code with known numbers and no repeats. With 1 item there are 6 possibilities with 2 you only have 5 choices after the first if you don't repeat the same item. So for 6 items the equation is as follows 6*5*4*3*2= 720 possible combinations of 6 items.