# Algebraic Expressions Lesson 4

### Using Negative and Decimals as Values for Algebraic Symbols

Haleemah and ET work to model a scooter trip by relating the scooterâ€™s start location, trip time, velocity, and end location. Using this context, they begin to think about the different kinds of values that an algebraic symbol can take on.

##### Episode 1: Making Sense

ET and Haleemah make sense of the scooter applet and create a conjecture for the relationship between velocity, trip time, starting location, and ending location.

##### Episode 2: Making Sense

The students continue exploring the scooter applet and see if their conjecture holds for negative and decimal values.

##### Episode 3: Exploring

ET and Haleemah apply their method for finding the scooters ending location and discover a mistake.

##### Episode 4: Repeating Your Reasoning

The students apply their method for finding the ending location for a scooter trip that starts at 4 meters and lasts for 3 seconds to two more trips with different velocities.

##### Episode 5: Exploring

Haleemah and ET generalize their method and write an algebra equation that relates the scooterâ€™s velocity and its end location.

##### Episode 6: Reflecting

ET and Haleemah reflect on their generalized algebraic expression and think about what would happen if their variable, v, was a negative number.

##### Episode 7: Reflecting

ET and Haleemah reflect on their generalized algebraic expression and think about the values their variable could represent.