Can you tell the weight of a bus by looking at it?

I just finished reading Geekspeak: How Life + Mathematics = Happiness, a birthday gift. It’s a short but illuminating read that explains why math is a useful day-to-day tool. It can help you answer the questions that curious minds – perhaps your own – pose in the course of daily life, especially if you know when and how to approximate numbers. It can help you test the relative veracity of political claims and media reports.

For example, the authour explains how to test the truth in some old sayings, such as that every breath you take contains some air that was in Julius Caesar’s lungs (true, but probably only about five molecules’ worth), or that there are more people alive than have ever died (false, about four times as many have died than are now living). If you want to know how to estimate how many piano tuners there are in Boston, or how many houseflies it would take to pull your car, read this book.