Lesson objective: Use a factor chart to determine if a number is prime or composite.

This lesson helps to build procedural skill with determining if a number is prime or composite. A t-chart is used here because it supports students' work with factor pairs and allows students to list factor pairs in an organized way. This work develops students' understanding that a prime number is a whole number greater than one with only one factor pair and that a composite number is a whole number greater than one with more than one factor pair.

Students engage in Mathematical Practice 3 (construct viable arguments) as they create t-charts to justify their conclusions on prime and composite numbers.

**Key vocabulary:**

- composite
- factor pair
- prime
- t-chart

**Special materials needed:**

- 2 dice
- 2 sets of game board markers