**Integral Centrifuge**

##### (MathPickle, 2016)

This puzzle is for students learning about the multiplication of integers. It deals only with the integers +1 and -1, so things are kept focussed on ridiculously easy multiplication with the backdrop of an unsolved problem. The slide above shows a successful and unsuccessful attempt for large centrifuges. Students should start small! They should start by discovering centrifuges like the one pictured below.

Mathematicians may recognize that this puzzle is inspired by Barker codes. Unlike linear Barker codes, here I’m playing with rings.

**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!

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

##### MP3 Work together!

This is collaborative problem solving in which students discuss their strategies to solve a problem and identify missteps in a failed solution. MathPickle recommends pairing up students for all its puzzles.

##### MP6 Be precise!

This is where our 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!

One of the things that the human brain does very well is identify pattern. We sometimes do this too well and identify patterns that don't really exist.