Obviously a parent or teacher would explain why/how it works, and what a percentage is, rather than just the mechanics. That really wasn't my point. The point is learning the terminology. OF means multiply when you are dealing with a fraction (and yes, I realize that you don't necessarily need to rewrite as a decimal, you can rewrite as a fraction. My point is that it needs to be rewritten. You can't multiply it when it's written as a percent).