[jyl]

In case you want to test your math skills against the kids in my daughter's algebra class.

You have seven friends and an unknown quantity of chocolates. You give the first friend half of your chocolates, plus one. You give the second friend half of your remaining chocolates, plus one. You give the third friend half of your remaining chocolates, plus one. And so on. After you have given chocolates to all seven friends, you have one chocolate left. How many chocolates did you start with?

And how did you solve the problem?