I'll get straight into it:
The problem I'm working on is described as a lock with 12 buttons where in a certain combination, a button can only be pressed once, and the combination could be in length anywhere between 1 and 12. It asks me to calculate the number of possible combinations that would open this lock, and a "pseudo code" example of how a computer would find the combinations themselves. Now, this last part doesn't seem like it fits here, but I threw it in anyway.
So what is the process for this? I was thinking along the lines of combinations formula where the pool is 12 and choose is 1-12, and they are all added up, but I don't think this is correct as it gave me a very large number.