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📖 What Are Independent & Dependent Variables?

Standard 6.EE.9 – Learn the key vocabulary before diving into the activities!

🎮

Independent Variable

The variable YOU control or change.
It is the input — you choose it.
It does NOT depend on anything else.
Goes in the first column of a table.

🎯

Dependent Variable

The variable that changes because of the independent variable.
It is the output — it's the result.
It DEPENDS on the input.
Goes in the second column of a table.

💡 Memory trick: Ask yourself — "Which variable CAUSES the change?" That's the Independent. The one that gets affected is the Dependent.

🌍 Real-World Examples

🚗
Road Trip
Independent: hours driven
Dependent: miles traveled
Miles depend on how long you drive.
🍕
Pizza Party
Independent: number of pizzas
Dependent: total cost
Cost depends on how many pizzas you order.
🌱
Plant Growth
Independent: days of sunlight
Dependent: height of plant
Height depends on sunlight received.
💰
Babysitting
Independent: hours worked
Dependent: money earned
Earnings depend on hours worked.
📚
Reading Challenge
Independent: books read
Dependent: points earned
Points depend on books read.
🎵
Music Downloads
Independent: songs downloaded
Dependent: total data used
Data used depends on songs downloaded.
🔑 Key Questions:
✅ "Which variable CAUSES a change?" → Independent
✅ "Which variable IS CHANGED by the other?" → Dependent
✅ "Which one do you choose/control?" → Independent

🧩 Matching — Drag Into the Right Box

👇 Each card below has a highlighted word or phrase. That highlighted part is what you need to decide about.
Drag the card into either the Independent Variable box or the Dependent Variable box.
You'll find out right away if you're correct! ✅❌
🚗 A car travels for 3 hours. The longer you drive, the farther you go. → Hours driven
🚗 A car travels for 3 hours. The longer you drive, the farther you go. → Miles traveled
🍕 The more pizzas you order, the higher the bill. → Total cost
🌱 A plant gets more sunlight each day and grows taller. → Days of sunlight
💰 A babysitter earns $10 for each hour worked. → Money earned
📚 The more books a student reads, the more points they earn. → Number of books read

🟡 Independent Variable
(the cause — what you control)

🟢 Dependent Variable
(the effect — what changes as a result)

🗂️ Sort It!

👇 Each card below shows a full scenario. The highlighted part is what you need to classify.
Drag it into either Independent Variable or Dependent Variable.
You'll get instant feedback after each drop! ✅❌
🎸 The more hours Marcus practices guitar, the better he plays. → Hours of practice
🎸 The more hours Marcus practices guitar, the better he plays. → Skill level gained
🛢️ A truck uses more fuel the longer it drives. → Number of gallons used
🍽️ A family buys more groceries when they eat more meals. → Number of meals
🍽️ A family buys more groceries when they eat more meals. → Total grocery cost
🚗 The farther you drive, the more miles you put on the odometer. → Total miles driven
🍔 The more snacks you eat, the more calories you consume. → Total calories eaten
🏷️ The more items you add to your cart, the higher the price. → Total price

🟡 Independent Variable
(the cause — what you control)

🟢 Dependent Variable
(the effect — what changes as a result)

✏️ Fill in the Blank

Read each scenario. The highlighted word or phrase is exactly what you need to classify. Choose Independent or Dependent!

🧮 In the equation y = 4x, you pick a number and substitute it in for x. Then the equation calculates the answer for y.
The variable x is the
🧮 In the equation y = 4x, after you substitute in x, the equation calculates the value of y as the result.
The variable y is the
🐶 Every time you give your dog a treat, it wags its tail more. You decide how many treats to give — that's what you control. The number of treats you give is what causes the change.
Number of treats is the
🐶 You give your dog treats and notice its tail starts wagging. The number of tail wags changes depending on how many treats you give — you don't control it directly.
Tail wags is the
🌡️ On a hot summer day, the temperature rises and ice cream sales go up. The temperature outside is what's causing people to buy more ice cream.
Temperature is the
🌡️ As the temperature rises, the shop owner notices ice cream sales increase. This number changes based on how hot it is outside — the shop owner doesn't control the weather!
Ice cream sales is the
🛒 Every time you add another item to your grocery cart, the bill goes up. You decide which items go in the cart — you're in control. The number of items in the cart is what you choose.
Items in cart is the
🛒 You add items to your cart and watch the total grocery bill go up with each addition. You can't set the total directly — it's calculated based on what you put in.
Total grocery bill is the

📊 Variables in Tables

Read each scenario. The highlighted column name is what you need to label. Use the dropdown to identify it!

🚴 Table 1 — Biking

Jada decides how many hours she bikes each day. The more hours she bikes, the farther she goes. You need to label each column — ask yourself: which one does Jada control?
Hours Biking Miles Traveled
1 10
2 20
3 30

🍪 Table 2 — Cookies

A baker controls how many cups of flour she uses. The more flour, the more cookies. Which column is the cause and which is the effect?
Cups of Flour Cookies Made
1 12
2 24
3 36

💡 Table 3 — Light Bulbs ⚠️ Tricky!

⚠️ Watch out! The first column is NOT always the independent variable. A light bulb stays on for a certain number of hours. The longer it's on, the more electricity it uses. Which column is the CAUSE?
Electricity Used (kWh) Hours On
2 1
4 2
6 3

🔢 Build the Equation!

Read each scenario. The highlighted variable tells you which one is which. Build the equation by choosing the correct variable for each side!

🛵 Scenario 1: A scooter travels 15 miles for every hour driven. You choose how many hours (h) to drive — that's what you control. The distance (d) depends on how long you drive.

Build it → dependent variable = 15 × independent variable

=15×
🎮 Scenario 2: A gamer earns 50 points per level. The player decides how many levels (L) to complete — that's the input. The total points (p) earned is the result.

Build it → dependent variable = 50 × independent variable

=50×
🥤 Scenario 3: A smoothie needs 3 fruits per serving. You pick how many servings (s) to make — that's your choice. The total fruits needed (f) is calculated from that.

Build it → dependent variable = 3 × independent variable

=3×
🔑 Pattern: Always → dependent = rate × independent. The dependent variable is always on the left side (it's the output/result)!