Let's say you're in the babysitting business and you like to keep a log of whom you are babysitting. So in the last month, you babysat six children and you wrote the ages of all six children in your log. But then when you go back to your log, you notice that some blue ink spilled over one of the ages and you forgot how old that child is. And at first you're really worried, your whole system of keeping records seems to, you know, you've lost information. But then you remember that every time you wrote down a new age that month, you recalculated the mean. And so you have the mean here of being four, the mean age is four for the six children. So given that, given that you know the mean and that you know five out of six of the ages, can you figure out what the sixth age is?