## Two Classic Puzzlers from Cartalk

Puzzler 1: Every two-digit number can be represented as AB, where B is the ones digit and A is the tens digit. Right? So for example the number 43, A is 4 and B is 3. Imagine then that you took this two-digit number and you squared it, AB x AB, and when you did […]

## The App Store – 10 Billion

This great idea comes from Dan Meyer and mister2pi. When will the App Store hit 10,000,000,000?

## Developing Math Intuition

Great post: http://math-blog.com/2011/01/13/developing-math-intuition/ Our initial exposure to an idea shapes our intuition. And our intuition impacts how much we enjoy a subject. What do I mean? Suppose we want to define a “cat”: Caveman definition: A furry animal with claws, teeth, a tail, 4 legs, that purrs when happy and hisses when angry. . . Evolutionary […]

## Today is brought to you by the number 73

Here’s a great set of facts about the number 73 (a Chuck Norris Number, sidenote I might grow to like that show but I can’t stand the laugh track): The mirror of 73, the 21st prime number, 37, is the 12th prime number. The number 21 has factors 7 and 3. In binary, 73 is a palindrome […]

## Two Great Puzzlers from Cartalk

1.  Cats, Dogs and Mice – Oh My! RAY: You’re given a hundred dollars and told to spend it all purchasing exactly a hundred animals at the pet store. Dogs cost \$15. Cats cost a buck, and mice are 25 cents each. TOM: Let me get this straight. You have to spend exactly a hundred […]

## SBG: One Small Success

This is a quick post describing one small reason (of many) of why I like SBG. The setup for the gradebook is as follows: each student gets 2 shots (in class) to quiz on each topic, the grade is out of 4.  They get one chance right after the end of the unit, and one […]

## Alcumus

From Webmaths: Pretty cool website, a bit like Project Euler, but with more approachable difficulty level:  http://www.artofproblemsolving.com/Alcumus/Introduction.php Sample Problem: The leveling up system they have could be an excellent way to get students addicted to solving some novel math problems.  There are ways (I haven’t explored them) to set up an entire class of kids […]