The problem is that if you have $55 in your wallet, and DVD’s cost $12 each. If we bought n DVD’s, how much money would we have left. M did this for n = 3 and n = 4. It may be instructive to do this for n = 5. The result would be negative. It means that if you bought 5 DVD’s, you would have to borrow. This would help clarify the meaning of negative numbers, an important concept they need to fully understand.