Rock – Low unique number game

(MathPickle, 2015)

“Rock” is the best MathPickle filler game for grades K-2. If you need five minutes of energetic math – try it. Each game takes about 45 seconds. This is part of the key to its success. Children who have not learned the art of losing are quickly thrown into another game before they have a chance to get sad. Try plotting the winning number. What is a winning strategy? Does the winning strategy depend on the number of children playing? Rules: 1) Everyone makes a rock shape with eyes closed. 2) Everyone secretly chooses a number 0, 1, 2, 3, 4, 5, 6, 7, 8, … 3) Teacher starts by calling out numbers consecutively starting at 0. 4) When a student hears their number being called they immediately raise a hand. 5) If more than one hand was raised – those students lose. They become your helpers. 6) If only one hand was raised that child wins.

As well as being an awesome game to provide number sense, “Rock” also gives students a quick experience of failure. There is no time for complaining because the next game starts immediately. Giving kindergarten students the resilience to deal with temporary failure is time well spent!

I think the universe is pure geometry – basically, a beautiful shape twisting around and dancing over space-time.

Antony Garrett Lisi

Standards for Mathematical Practice

MathPickle puzzle and game designs engage a wide spectrum of student abilities while targeting the following Standards for Mathematical Practice:

MP1 Toughen up!

Students develop grit and resiliency in the face of nasty, thorny problems. It is the most sought after skill for our students.

MP2 Think abstractly!

Students take problems and reformat them mathematically. This is helpful because mathematics lets them use powerful operations like addition.

MP3 Work together!

Students discuss their strategies to collaboratively solve a problem and identify missteps in a failed solution. MathPickle recommends pairing up students for all its puzzles.

MP4 Model reality!

Students create a model that mimics the real world. Discoveries made by manipulating the model often hint at something in the real world.

MP5 Know the tools.

Students master the tools at their fingertips - whether it's a pencil or an online app. 

MP6 Be precise!

Students learn to communicate using precise terminology. MathPickle encourages students not only to use the precise terms of others, but to invent and rigorously define their own terms.

MP7 Be observant!

Students learn to identify patterns. This is one of the things that the human brain does very well. We sometimes even identify patterns that don't really exist 😉

MP8 Be lazy!?!

Students learn to seek for shortcuts. Why would you want to add the numbers one through a hundred if you can find an easier way to do it?


Please use MathPickle in your classrooms. If you have improvements to make, please contact me. I'll give you credit and kudos 😉 For a free poster of MathPickle's ideas on elementary math education go here.

Gordon Hamilton

(MMath, PhD)