## Introduction

Class Openers and Math Talks are quick whole-class or small-group activities that can be used anytime during a math class to engage students in mathematical discussion and exploration. The activities below can be used with all ages of students.

Do you have ideas of your own to add to this list? If so, please email the Polypad link, a brief description, and perhaps a quick video overview to teachers@mathigon.org. Of course, we'll list your name when adding your activity to the collection.

## What are the 2 Cards?

Shuffle cards 1-10, draw two at random, and place them on the balance scale. Then, place two dice on the other side of the scale and have students predict the two cards. Roll the dice and have students update their prediction. Continue this process and add a 3rd or 4th dice if needed.

## Balance the Scale with 6 Dice

Roll the dice and have students discuss how to place the dice on each side of the scale so the scale becomes balanced. Depending on the age of students, they may quickly reach the conclusion that the sum of the dice must be even in order for the dice to have a chance at balancing the scale. Older students might want to explore the probability that the dice will balance the scale. Students of all ages can engage in good mathematical thinking simply by trying to balance the scale.

## Predict 50 Rolls

Students predict how many times each number on a single die will be appear in 50 rolls. Then, the perform the rolls and compare their results to their predictions. This task provides good practice for elementary students on working with number addition while also incorporating some probability and statistics ideas. See this video for an example of this task:

## Fraction Operations

Students choose a target number and an operation. Then, they roll 4 dice to create two fractions that will will yield a result as close to the target number as possible. Credit to Mark Labuda and Marian Small.

## Folding Nets

For each net, invite students to discuss with a classmate what will happen when you click "Fold Net." Then, invite a few students to share their predictions with the class, and then fold the net. After folding the blue one, repeat this routine with each net one at a time. After doing this math talk, your class will be ready for the one listed below.

## Will it Fold? What Will it Make?

Invite a student to create a 2D shape using a variety of Polypads that they believe might fold into a 3D object. Before clicking "Fold Net," have students share with the class what they predict will happen when you click "Fold Net." Depending on what happens, you could discuss how to change the net so it does fold, how to make it a closed 3D shape if it is not, what happens if you remove a Polygon, and more! Just use a blank canvas for this activity. Here are a few examples.