At a local ice cream shop, you can choose from a collection of 18 different toppings. If you want to choose at least one topping, how many different topping combinations are possible (assuming no repeat toppings)?
This becomes a question of subsets
The number of subsets of 18 elements is 2^18 or 262144
that would include the null set, in this case no toppings
So the number of different topping combinations would be
262143