PhET: Understanding Integers on a Number Line

Real-Life Integers

Display the following situations:

• A temperature of 10°F
• A temperature of -5°F
• A bank account balance of +$50
• A bank account balance of -$20

Ask students:

• Which values are above zero?
• Which values are below zero?
• What might negative numbers represent?

Co-Use Activity
Students work with a partner to sort examples into positive and negative categories and explain their reasoning.

Exploring the Number Line

Introduce:

• Integer
• Positive number
• Negative number
• Zero
• Opposite
• Absolute value

Draw a number line and discuss:

• Numbers increase to the right.
• Numbers decrease to the left.
• Zero is neither positive nor negative.

Co-Use Activity

Student A identifies an integer.

Student B identifies its opposite.

Partners switch roles.

Examples:

• 5 and -5
• 8 and -8
• 1 and -1

Exploring the PhET Interactive

Students access the Number Line: Integers simulation.

Teacher demonstrates:

• Placing integers on the number line
• Moving left and right
• Finding opposites
• Comparing values

Students observe:

• What happens as numbers move right?
• What happens as numbers move left?
• How far are opposite numbers from zero?

Co-Use Activity

Partners share a device.

• Student A = Navigator
• Student B = Recorder

Partners switch roles halfway through the activity.

Integer Investigation Teams

Activity 1: Locate the Integer

Using the simulation, students place:

• -10
• -4
• 0
• 3
• 8

on the number line.

Activity 2: Find the Opposite

Students identify opposites for:

• 6
• -2
• 10
• -7

Activity 3: Compare Integers

Determine which is greater:

• -3 or 5
• -8 or -2
• 4 or -4
• 0 or -1

Activity 4: Integer Walk

Using the simulation:

Start at 0.

• Move +5
• Move -3
• Move +2

Where do you end?

Repeat with several examples.

Team Challenge

Each pair creates an Integer Walk for another pair to solve.

Exit Ticket

1. Place -6 on a number line.
2. What is the opposite of 9?
3. What is the absolute value of -7?
4. Which is greater: -4 or 2?
5. Explain what happens when you move left on a number line.

Success Criteria
Students can:

✓ Identify integers on a number line.

✓ Determine opposites.

✓ Compare integers.

✓ Explain movement on a number line.

Co-Use Activity
Partners review responses before submitting individual answers.

Real-World Integer Scenarios

Students choose one scenario:

Temperature
The temperature is 5°F in the morning and drops 8 degrees.

What is the new temperature?

Banking
You have $20 and spend $35.

What is your balance?

Elevation
A diver starts at sea level and descends 15 feet.

What is the diver's elevation?

Co-Use Activity
Partners create one additional real-world integer problem and exchange it with another pair.