Math Clocks

I just spotted these on Amazon. I particularly like the one on top.

PUZZLE: Tabling the Question

I haven't done a math puzzle in a while, so here's an old one to strain the average brain. (And by that I mean my brain: in the past, my readers have solved these so fast it's almost embarrassing.)

Mr. Jenkins comes home to find his son Todd reading a comic book rather that working on his quadratic equations. He sets about berating the boy, when Todd interrupts him with a deal. "If I can pose a problem you can't solve, you have to finish my homework, and I can to finish my comic." Mr. Jenkins, considering himself something of a math whiz, takes this bet in a heartbeat.

Todd pushes a large, perfectly round table into a corner, with its edge touching both walls. He places a spot and then turns to his father. "That spot," says Todd, "is exactly 9 inches from one wall and 8 inches from the other. Without measuring the table, tell me its diameter."

My Jenkins puzzled and puzzled 'til his puzzler was sore, and then wound up finishing Todd's homework while the boy returned the adventures of Uncle Scrooge. Would you have done any better?

Be a Mathlete: World Math(s) Day

March 1st is World Maths Day according to The International Committee for Proclaiming Days for Things.

Actually, this one is proclaimed and run by an Australian e-learning company, but it seems to have caught on and the competition raises money for schools (which is good) and UNICEF (meh). You can tell it's not American because they call it "maths" rather than "math."

(Why do the Brits say "maths"? Because  the word is a contraction of "mathematics," which is a plural. Thus, technically, the contraction should also be plural. That may appear to make perfect sense, but since we won the Battle of Yorktown and they didn't, we're right.)

Anyway, back to World Math Day. Over 5 million kids from 218 countries are taking part in a 60-second math challenge by logging in to worldmathsday.com and answering a series of addition, subtraction, multiplication, and division problems. That makes it the biggest multiplayer session of the day.