I can guess your thoughts trick

I'm not a big fan of these various math tricks (such as how to multiply any two numbers between 11 and 19 or how to square some special numbers ending in certain digits) unless they increase students' understanding of the number system or math principles. Often they're just another thing to memorize that fades away quickly... at least with me.

But some people like them, and that's fine with me.

One particular kind of math "trick" is where you are told to think of a number, then do all sorts of manipulations with it, and then in the end... they know your number! How is that?

Here's one for you... it's neat, easy, amusing, and explains in the end how it works.

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Comments

Anonymous said…
How cute! I hadn't seen one of those puzzles end like that before. I use this kind of thing as an introduction to algebra, using manipulatives. My students have always enjoyed them. (Hat tip to Harold Jacobs, whose textbook Elementary Algebra does the same thing in pictures.)

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