## Southpaw Summations

August 13 is Left Handers Day.

It’s interesting to me that left-handers chose the 13th as a day to honor themselves, since the number 13 is often associated with a lack of luck. After all, the word sinister, which implies that something evil or harmful is about to happen, derives from the Latin word sinistra, which means lefthanded. It comes from the Latin word sinus, referring to the pocket on a toga that always appeared on the left side.

My brother-in-law has a shirt that says:

Everyone is born right-handed.
Only the strongest can overcome it.

“Interesting theory,” I said.

“It’s only one of two possible theories,” he informed me. “The other is that everyone is born left-handed, but only the strongest can maintain it.”

Most sources say that about 10% of the population is left-handed, and most statistics show that there are more left-handed females than left-handed males.

Interestingly, some studies have found that left-handedness is higher in math teachers than in the general population. In particular, a statistically significant difference was found for male math teachers. It’s also the case that left-handed students score higher in math on the SAT.

It has been suggested that those without a language bias in the left hemisphere of the brain, who are left-handed at a higher rate than the general population, would have an advantage in mathematical ability. For this reason, one researcher said that there is not a higher than normal occurrence of left-handers among the mathematically gifted, but rather that there is a lower than normal occurrence of right-handers.

This reminds me of a famous syllogism:

• Ten percent of all car thieves are left-handed.
• All polar bears are left-handed.
• If your car is stolen, there’s a 10 percent chance it was taken by a polar bear.

Given this information about mathematical ability, it stands to reason that polar bears may have a penchant for both grand larceny and integral calculus.

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The Math Jokes 4 Mathy Folks blog is an online extension to the book Math Jokes 4 Mathy Folks. The blog contains jokes submitted by readers, new jokes discovered by the author, details about speaking appearances and workshops, and other random bits of information that might be interesting to the strange folks who like math jokes.

## MJ4MF (offline version)

Math Jokes 4 Mathy Folks is available from Amazon, Borders, Barnes & Noble, NCTM, Robert D. Reed Publishers, and other purveyors of exceptional literature.