One of the most popular posts on this blog is one from October 2010: Maybe you are good at math and never knew it.

People get to it by searching all kinds of math-related anxiety phrases, such as “will I ever be good at math?,” “why am I not good at math?” and even some folks in the international crowd, who say, “I want to be good at maths.”

You may never read calculus books for fun, but you’re probably better at math than you think.

The original post was intended as inspiration. And here’s some more. Five clues that you could be good at math:

• 1) You can measure.

My mother, born in 1927, did not complete her high school education. Yet, she could convert recipes – doubling them, multiplying them by one-and-one-half with ease.

If a recipe calls for two cups (8 ounces) of water, and she were slightly increasing the recipe to 1.5 times, she’d put in three cups, or 12 ounces.

Hat tip to all the coffee baristas working with math every day.

• 2) You can automatically do base-12 math. Wait! Don’t stop reading!

Most of the numbers the average person works with are on the base 10-system; this includes counting cookies and dealing with money.

But, time is on a base-12 system. And it’s a beautiful system because it can be so easily quartered.

I bet that you move seamlessly between the two systems all the time without even realizing it.

This is huge. Your brain, FTW.

Don’t believe me? Here’s a simple example:

Say you have 75 cents in your pocket. Someone says, “I have double that.” You might automatically know that 75 cents, doubled, is $1.50. Similarly, three-quarters and three-quarters is one-and-one-half. Or, 75% + 75% is 150%.

That’s all base-10 math and you do it all the time.

Now, say you want to microwave something for one minute and 30 seconds. You put it in the microwave. It starts counting down. A few seconds later you realize, “Hey, there’s half the food on my plate as usual. I only want to microwave half that time.”

What is half of one-minute-and-a-half? Do you stop the microwave after 45 seconds? If so, congratulations — without even realizing it, you knew that on the base-12 system, 45 seconds is three-quarters, the same as 75 cents on the base-10 system.

If someone says, “I’ll be there in 90 minutes,” do you automatically know that that is one-and-one-half hours? Congratulations, you can do simple base-12 math calculations, which is almost like thinking in a foreign language.

On a base 12 system, 1:30 (one minute and thirty seconds, or one hour and thirty minutes) is the same as 1.5 on the base 10 system.

• 3) You budget your money well.

Not everyone can do this, but some of us are instinctive about when our spending drifts up. That means that we are doing instinctive math. It is in our head.

Without using a calculator, or a pen or pencil, my father could estimate his grocery bill pretty accurately when he got to the check out. It may not be rocket science, but he had a head for numbers.

• 4) You don’t bump your car (or bicycle) into things.

Spatial awareness is a beautiful thing. (I lack it, sadly, which is why the side of my car is scratched and why my mirrors are busted. To all the good women drivers, I’m sorry for pulling down the average.)

I’ve met people who claim to not be good at math but who have excellent spatial awareness.

During my recent vacation in Ireland, we rented two cars and two brave members of the family drove the cars on the left. I was in the second car, and so I could watch as my mother-in-law’s brain adjusted to the new dynamic. At first, she was hugging the left side of the road, but she gradually began to own her lane and operated the car like a pro.

Brilliant!

I don’t think I could have done it — I walk into walls in broad daylight.

What does spatial awareness have to do with math? It is a building block for understanding geometry.

• 5) You can calculate a tip in seconds

In the United States, standard rates for tipping at restaurants is 15% to 20%.

Without fail, I tip 20%. I like to think it’s because I’m generous, but I also think that it’s faster to do the calculation that way. On a double-digit bill, I’m less likely to screw up if I just double the leftmost digit.

Say the bill is $50. Then a 20% tip is easy – just double the five, which is the leftmost digit. A $10 tip is 20% of a $50 bill.

It takes another step to do a 15% tip. You have to take $50, divide by 10, for $5, then add half, $2.50, for a total of $7.50. Too much thinking.

And the waiter is better off too. Win win.

 

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Photo credits:

Cookies, courtesy of Flickr user scubadive67.
Prague clock, courtesy of Flickr user simpologist.
Hertz “drive on the left” photo, my own.

 

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