Two hundred thirty eight thousandths. I had to seriously confirm that with multiple people (who also had only a rough idea) because you don't even use that very often if at all past elementary (unless your teacher is super strict). XD
Answer:
The answer is 5,368,709,120
For the first digit there are 7 choices. For the second digit there are 6 choices (because we can't use the same one again). And so on, until there is only one choice for the last digit.
The number of possible codes is this:
7*6*5*4*3*2*1 = 7! = 5040
Each student would get 1.6 brownies
