## Lesson: Functions

Developing the Concept

Now that students have been reintroduced to one-step functions involving addition and subtraction, they will focus on one- and two-step functions involving addition, subtraction, multiplication, and division.

**Materials:** overhead projector and blank transparency; 4 congruent triangles, 2 congruent circles, and 3 congruent squares for use on the overhead; 20 two-step functions written on index cards; Function Machine (PDF file) sheets for each pair of students (see below).

**Preparation:** Prepare index cards with two-step functions written on them. (You may wish to laminate the cards.) Copy Function Machine (PDF file) sheets for each pair of students.

**Prerequisite Skills and Concepts:** Students should be able to write and solve equations. They should be able to write the equation and create the function table for simple functions involving addition and subtraction.

**Wrap-Up and Assessment Hints**

Have students work in teams of two. Give each team a Function Machine (PDF file) sheet.
The first team takes a prepared index card with a two-step function on it. The second team picks a number. The first team applies its function to that number and gives an output number. This continues until the second team correctly identifies the function. The teams swap roles and play again. The team that correctly names the function in the fewest tries wins that round.