Numbers are an essential part of life, so we better learn to live with them. It’s often said that the language of nature is mathematics, so if you’re going to be a scientist, you’re going to need math. True enough. But non-scientists need numbers too. Keeping a bank account, getting a mortgage, and providing car insurance all require keeping track of numbers. Nor can you get by without probability and statistics. Probability and statistics tell us how to manage risk.
All of life involves risks, but some risks are a lot worse than others. For every 100 million miles driven on American roads by cars, one driver dies. But for every 3.3 million miles driven on American roads by motorcycles, one rider dies. Your chances of dying are thus 30 times more likely on a motorcycle than in a car. Maybe that’s a risk you didn’t know. Maybe you don’t care. But your spouse, who’s taking out life insurance on you, just may.
Numbers are often abused. Joseph Stalin, head of the former Soviet Union and cynically willing to break any treaty, is said to have remarked, “Paper doesn’t care what’s written on it.” Numbers, likewise, don’t care what people do with them. For this reason, numbers are easily abused. John Paulos’ Innumeracy: Mathematical Illiteracy and Its Consequences, Darrell Huff’s How to Lie with Statistics, and Peter Olofsson’s Probabilities: The Numbers That Rule our Lives are very useful for keeping numbers from being used to deceive us.
Because numbers are everywhere, it’s useful to hone your arithmetic skills. Often when someone tells you the outcome of a calculation, it’s good to do what engineers call a “sanity check” — are the numbers even in the right ball park for the calculation to be correct? If, for instance, someone computes a probability of 5.7, you know something went radically wrong because probabilities are always numbers between zero and one.
There are lots of useful resources for developing your basic arithmetic skills. A classic is The Trachtenberg Speed System of Basic Mathematics by Jakow Trachtenberg. Trachtenberg, a Ukrainian engineer, developed methods for high-speed arithmetical calculations while in a Nazi concentration camp (he did this as a way to keep his sanity). Numerous spin-offs have been published since. One that’s useful for younger students is the Brainetics.
Numbers make the world go round, not just the world out there but also your own personal world. Numbersleuth is here to help you make sense of the numbers that are constantly bombarding you.