The woman, probably in her 30s, said, “What’s 48 times 2?”
I said, without blinking, “96.”
She stared at me for a couple of seconds, then said, “Are you a teacher?”
Apparently, only teachers and – oh, I don’t know, mathematicians? – are supposed to be able to do math.
The world is afraid of math. Or so they say. A lot of us avoid math not because we’re too dumb to understand it but because sometimes it takes a little effort that we’re not willing to put forth.
Forty-eight times two shouldn’t take that much work. I knew that one in a flash, but what if she’d asked, “What’s 48 x 5?”
All right, that would have taken me a little longer. But only by a couple of seconds, because I have a shortcut. With any big-ish number multiplied by 5, I first multiply it by 10 (just add a zero), then divide the result by 2 (because 10 / 2 = 5). So 48 x 5 looks like this:
(48 x 10) = 480
480 / 2 = 240
This is why I was overjoyed to discover the book The Joy of X: A Guided Tour of Math, from One to Infinity by Steven Strogatz. (Besides that, The Joy of X is an awesome title, don’t you think?) Strogatz makes learning math fun!
OK, maybe it’s fun only to geeks – you’ve got me on that one.
Maybe fun is not why you should read this book. But how about reading it because you want to stop being “afraid of math,” “no good at math” or “math-phobic” – or maybe you just want to learn some new party tricks? 🙂
A lot of kids grumble, “I’ll never use this in real life.” I beg to differ. Here are some of the professions that use math all the time:
- Carpet layers.
- Real estate agents.
- Restaurant wait staff.
- Computer programmers.
- App developers.
- Mathematicians. 🙂
Get my drift? For all the students who complain about having to learn math, there is a professional out there who couldn’t make a living for very long without using it.
WE ALL NEED MATH
But we have calculators, you say.
I was in a Kmart in California several years ago when the electricity went out. A bunch of people were stuck at the checkout line because the clerks couldn’t check the merchandise without a computer.
What if you’re somewhere that you need to do some basic math, and your phone battery goes dead? How are you going to leave a tip for your server?
I usually leave 20 percent, but the standard is 15 percent. Say your bill comes to $24.80. Here’s how to figure a 15 percent tip, using your brain as a calculator:
A 15 percent tip is the same as a 10 percent tip PLUS half of a 10 percent tip (5 percent), so …
Divide the bill by 10, then halve that amount and add the two results together:
$24.80 / 10 = $2.48
$2.48 / 2 = $1.24
$2.48 + $1.24 = $3.72
To make it easier, you could round up the two resulting quotients ($2.48 and $1.24) before adding them, because I find it easier to work in 25-cent increments.
$24.80 / 10 = $2.48 (round up to $2.50)
$2.48 / 2 = $1.24 (round up to $1.25)
$2.48 + $1.24 = $3.72 (or $3.75)
I made up the examples above, but this is how the author of The Joy of X goes about explaining algebraic concepts that we use in our everyday lives. Bet you never thought of tipping as an algebraic exercise, did you?
See, math isn’t evil. It just takes some thought.
Strogatz has fun with his book. In the quote at the beginning of this post, Humphrey the Sesame Street critter is placing an order for fish for six penguin guests at the Furry Arms Hotel. He calls out the penguins’ orders to the kitchen: “Fish, fish, fish, fish, fish, fish.” Ernie then proceeds to enlighten Humphrey as to the virtues of the number 6. Six is a shortcut. Humphrey could have saved himself (and the cook) some time by telling the chef, “Six fish!”
I don’t know about you, but I’ll take all the timesavers I can get. That’s what my two examples are. If you learn the concepts, they will save you time.
ORDER OUT OF CHAOS
One of the reasons I like numbers so much, I suppose, is that they are orderly. As Strogatz says, “They obey certain laws and have certain properties, personalities, and ways of combining with one another.”
That gives me great comfort in a world of chaos.
Yet, as Strogatz states, the language of math can also be elegant and artsy (vs. strictly logical and science-y):
“It’s the same convention as in Lionel Richie’s immortal lyrics ‘She’s once, twice, three times a lady.’ (‘She’s a lady times three’ would never have been a hit.)”
Forget that he got the lyrics slightly wrong (it’s “YOU’RE once, twice …); he made his point.
Strogatz uses not only formulas but graphic elements to illustrate his points. This is one of the great things about the book. My examples are just words; Strogatz’s are words plus visuals. It’s especially helpful when he gets into concepts a bit deeper than 3 x 7. (He uses rocks to illustrate squaring a number, slices of pie to illustrate a fraction, and so on.)
He also uses stories, because he knows that stories are what help us to remember challenging concepts. Take, for instance, this vitally important formula for putting all the superficial people of the world at ease:
In keeping with the spirit of fun that Strogatz maintained throughout this thoroughly enjoyable book, I want to share one of my favorite scenes from one of my favorite Hepburn and Tracy movies, Desk Set. (If you don’t want to watch the whole 9 minutes, start at the 2:45 mark. After it ends, wait a few seconds for the next segment, or you’ll never know the answer to the Harry and Grace riddle!) This is classic Tracy and Hepburn:
In study after study, researchers have found that challenging the brain improves a multitude of functions in our bodies. If you’ve always considered yourself “not good at math,” step outside your comfort zone and check out The Joy of X. Would you rather rely on a machine to do all your calculations for you, as did the computer operator in Desk Set (sorry, you’ll have to rent the movie to meet her), or would you rather expand your mind and live well? One way leads to boredom; the other leads to a longer, healthier, more fulfilling life.
You do the math.
What is your favorite math tip? I love collecting shortcuts; share, please!
Tomorrow: Y is for YOU!
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