This will be my last post about teaching math. In a day or two I will explain why.

For now, here is one last problem that I made up that I like. It is to help highlight the difference between percent change and percentage points:


Alfred and Anna have savings accounts at The Bank of Hubert’s Left Toe (a very respectable bank). They notice that the interest rates have gone up this year.

Alfred says, “That was lame, we are only earning 1,5% more money now.”

Anna responds, “No, you are mixing up percentage points and percent change. We are actually earning 24% more money now. That’s a big change!”

Assuming Anna is right, what percent is the interest now after it has gone up?