There’s a great article on the Atlantic website about how numbers confuses consumers. Actually it’s all psychology. Most people never stop and do the math, and their gut feeling invariable steers them wrong.
Here’s the opening sentence of the article. Quick! Which is the better deal?
You walk into a Starbucks and see two deals for a cup of coffee. The first deal offers 33% extra coffee. The second takes 33% off the regular price. What’s the better deal?
It turns out that most people say (wrongly!) that the two offers are equally good. Stop and do the math!
Take a quick look at the article’s comments. It being the internet and all, the commentators immediately go off the rails.