My younger son is fascinated by dice. He’s always inventing little dice games and really loved our project about non-transitive dice:

Non-Transitive Grime Dice

Today was sort of a dream come true for him as we got the final batch of supplies delivered for his school’s Family Math night. He had questions about some of the contents 🙂

A different box had something much more interesting – a giant bag of dice!

I asked him what he wanted to do with the dice and the first thing he wanted to do was roll all of the dice and see if we got all 6’s.

Turns out that we didn’t 😦

However, there were some other questions – how likely was it that we would have gotten all 6’s? It was lucky that we’d recently talked about the probability of various Powerball outcomes:

Never Tell me the odds – talking math and Powerball

He remembered a little bit about calculating probabilities like this and told me that the chance of getting all 6’s was (1/6) to the power of however many dice we had.

Next I asked him how many 6’s he expected we’d get. That led to arranging the ~350 dice into 6 groups. We had to leave for an activity he has on Monday nights, but I’d really like to ask him why he thinks the groups aren’t all the same size. Maybe that’ll be tomorrow morning’s project.

I’m not actually using these dice for any of the project I’ll be doing, but I’m very impressed with the ideas and projects that people have done in prior years. There’s probably 3 months worth of really great projects in these boxes – the people running the event in the past have really put a lot of thought into the projects that they’ve chosen to share with the kids.

[update from the next morning – here’s his description of what he was doing and what he was thinking about]


A review of “On the Dot” by Gamewright

Doing some prep work for Family Math night at my younger son’s school, I ran across a really neat game that had been used in prior years – On the Dot by Gamewright:

Sadly the game has been “retired” so I don’t think you can by it on Gamewright’s website, but I did see some for sale on Amazon.

Game play seems simple enough – you try to recreate a specific pattern of dots using 4 cards that you hold in your hand. Here’s my 4th grade son trying out a few examples:




After those examples, I asked him what he thought of the game and what math ideas he thought were part of the game:


I really like this game – it is easy to learn how to play and gets kids thinking about all sorts of math-related ideas from problem solving, to symmetry, to counting. It was also kind of fun to follow my son’s idea that the cards are not commutative.

So, a great game for kids. Sorry to hear that it has been retired, but get it on Amazon while you still can!

Revised Family Math night for Grades 2-3

I was originally planning on using Anna Weltman’s Loop-de-Loop activity for the Grade 2-3 Family Math night, but the 4th grade classes at the school actually did the activity already. I’m happy and sad about that, but I don’t want to spoil it for the future if the school wants to keep using it. It is really fun.

Instead, having just bought Patterns of the Universe, I think I’ll replace Weltman’s activity with a coloring activity.

Our two projects with Patterns of the Universe are here (with a link to the first one in the link below):

Patterns of the Universe Part 2

I’m also thinking of giving away a copy of the book at the event. For the coloring activities I’ll use the ones I also plan to use at the K-1 night from Math Munch:

Coloring sheets from Math Munch

I think this will be a good intro activity and also allow the people who are running late to not really be lost as the arrive.

Topic 2 will be unchanged – the Fold and Cut theorem. Hopefully we’ll be able to introduce the topic with Katie Steckles’ awesome video:

Here are some of the projects we did after seeing this video:

Our Fold and Cut project

Fold and Cut part 2

Fold and Cut part 3

The topic that I’d like to keep in my back pocket if we have extra time is the problem we studied after I saw Larry Guth lecture at MIT:

Larry Guth’s “No Rectangles” problem

This project is pretty open-ended, especially in terms of amount of time needed. The problem with a 3×3 square is interesting all by itself (and accessible to 2nd and 3rd graders). The 4×4 is harder, but would be fun to talk about with a large group – I’m sure the kids will have lots of different ideas. The nice thing about this problem is that it gives kids (and parents!) a taste of the kinds of problem math researchers think are interesting.