> how one year a variable would mean one thing and the next
> year it would mean something else
I'm probably misunderstanding what you mean, but isn't that the purpose of a variable? In programming, a variable foo in one method which represents Widget objects is completely independent from a variable foo in another method which represents Gadget objects. In math, solving for X in one problem might be to find the missing angle X, but in another problem it might be to determine the elapsed seconds X.
I'm not disagreeing that variables are meant to be variable.
However, it's important to teach context behind variables before asking an 11 year old to solve them or else it becomes a point of confusion. They are asked to use rote memorization to complete the calculations but they don't seed their memory before asking.
