Modeling is one of those things that we all want to put in our classes, but so many of the pre-made activities stink. But check out this activity that Dan Meyer put together with the help of Desmos.

## problem

1

Jul 13

## Math Vocabulary

One thing that I notice is particularly hard to impart in my online classes is mathematical vocabulary. My online students can be very technically proficient in key skills without being able to talk about them very well. I always notice this when they come in for office hours and we’re talking about a particular problem. I’ve been brainstorming different ways to develop vocabulary remotely. Here is my latest. I’m not sure what the name for these are. (Guessing: pictogram?) But we’ve all seen these in different games. You have a series of pictures indicating a word. See if you can guess these? And let me know what you think of the exercise.

15

May 13

## Turning Point

Lee Bradley is at it again. This problem is inspired by one of his tutoring sessions in the ASC. Follow the link. Enjoy the goodness.

Thanks, Lee!

4

Mar 13

## Colossal Number Problem

Lee Bradley posed another great problem. Check it out over at his site, Prime Puzzle.

27

Aug 12

## Math + Mind Tickle

I place $20 in a box.

So do you.

Now the box contains $40, and we both know it.

I sell the box to you for $30.

And we both walk away with a $10 profit.

Jay sent over a link this great problem. It’s from one of my favorite blogs Futility Closet. This is the perfect kind of problem to throw out in class…easy to remember and easy to think through in a few minutes. What’s lovely is that initially it seems so plausible and yet impossible that they both profit $10. It reminds me of a Nova show (embedded below) I was watching on neuroscientists studying magic. Most tricks rely on our visual system’s strong bias toward detecting and anticipating motion. I feel like this problem and ones like it trick our reason, possibly with the momentum of language? Whoa, that got deep! Better stop right there.

Watch Magic and the Brain on PBS. See more from NOVA scienceNOW.

10

Jul 12

## Alice + Logic

I loved this logic puzzle from Lewis Carroll’s diary that I found at Futility Closet. Enjoy!

19

Jun 12

## Scharezade + Math

My favorite puzzler, Lee, over at primepuzzle sent this problem in. Have fun!

http://storynory.com/2010/08/09/the-1001-nights/

What are the lengths of the sides of the smallest similar triangle?

“A terrible sultan marries a new bride every night, and in the morning he executes her. Only Sherehezade, the greatest story-teller the world has known, has a chance to soften the heart of the man with a tyrannical grudge against all women.”

It probably won’t take you 1001 nights to solve this one but in honor of Sherehezade we present the following challenge:

Can you find a right triangle that has a hypotenuse of 1001 and sides that are whole numbers?

What are the lengths of the sides of the smallest similar triangle?

5

Mar 12

## Sequence Problem

This one comes from puzzle/problem master Lee Bradley.

0, 3, 18, 69, 228, 711, next?

9

Jan 12

## Shopping + Math

I’ve been driving past this sign on the freeway for the past month, and thought this problem up.

Say you’re in the market for a necklace. You want to give mom something nice for the holidays. At Beckers you find a great necklace, it’s only $100 and they have this awesome deal where you might get it free if it snows on New Years day. But before you buy, you step across the street to Lux, Bond, and Green. They happen to have the same necklace. If the LBG price is only $50 where would you purchase the necklace? I think that has a pretty easy answer, but what about if the LBG necklace costs $95. Where do you buy the necklace?