## Dear Kid,

Today is the tenth day of the tenth month of the tenth year (assuming you started counting 10 years ago), so it seems appropriate to talk about the number 3.

Just kidding, the number 10.

I was going to share 10 fabulous facts about the number 10. But there are too many fun facts to stop at ten. Then I thought about 10 times 10 facts—until I realized that no one wants to read (or write) 100 facts.

So here are a bunch (I counted) of seriously interesting (mostly) facts about the number 10.

We (or at least most of us) have 10 fingers and 10 toes. Which is useful considering that most numbers we deal with are in base 10 (and that’s not even counting—get it, counting—the metric system). Also, the length of your hand (if you’re an adult) is a tenth of your height.

Number 10 Downing Street is the home of the British Prime Minister. But only if you say “Number 10” in a British accent.

“Deca” means ten (you knew that). But did you know that “decimate” really means to reduce by a tenth? If you write the number 10 twice (1010), you get the number ten in binary. Now that’s cool.

Ten is a triangular number (think about how bowling pins are arranged: 1+2+3+4). It’s also a tetrahedral number (very few people care).

There are 10 acres in a square furlong. (I never knew that, did you?)

Crabs, lobsters, shrimp, and other crustaceans have 10 legs. This makes them very tasty (but difficult to find shoes for).
A \$10 bill is also known as a “sawbuck.” The traditional 10th anniversary gift is tin, while the modern gift for the 10th anniversary is diamonds. That’s a lot of sawbucks.

There are 10 Lords A-Leapin’ according to the song. Capricorn (the sea-goat) is the 10th sign in the Zodiac. (Sea-goat? What on earth is a sea-goat?)

There are 10 provinces in Canada, eh? Virginia is the 10th State in the Union.

The number 10 is very important in sports, because it is the maximum number of events most people can watch at any one time. (I’ve watched you flip channels!) The decathlon has ten events. In auto racing, driving a race car at ten-tenths means driving as fast as possible. There are 10 yards in a first down, and ten yards in a football endzone. A basketball hoop should be hung 10 feet above the ground. There are ten players per side in lacrosse. The top score in gymnastics is 10 (except it isn’t anymore). Surfers try to Hang 10.

Odysseus traveled for 10 years (and that was before the invention of frequent traveler miles).

There are 10 commandments (plus “Pick your stuff up off the floor!). There were 10 plagues (the 11th may be the floor of your room). There are Ten Sephirot in the Kabbalistic Tree of Life. In Hinduism, Lord Vishnu appeared on the earth in 10 incarnations.

The Richter scale is measured in tenfold increase of energy. There are ten official ink-splats in the Rorschach inkblot test. The atomic number for neon is 10 (which you can write in neon).

Ten is the number you count to when you need to take a moment, and you take 10 when you need a longer break. We love Top Ten Lists, and searching for the perfect 10.

10-4 good buddy.