Grade 5 Math and Science Worksheets on Cars and Mechanics for 14-Year-Olds

Instructions

1. Read carefully: Each section focuses on a different part of being an automotive technician.
2. Show your work: Use the space provided or a separate sheet of paper to show how you calculated your answers.
3. Use the hints: If you get stuck, look for the Mechanic's Tip in each section.
4. Check your units: Make sure to label your answers (e.g., liters, miles, inches, or dollars).
5. Complete the Challenge: The final section is an optional task for those who finish early.

Section 1: The Tool Box (Fractions & Measurement)

Mechanics use wrenches measured in fractions of an inch. To work quickly, you must know which wrench is larger or smaller without guessing.

Task: Arrange the following wrench sizes from smallest to largest.

Sizes: 1/2", 1/4", 3/4", 3/8", 5/8"

1. __ (Smallest)

2. ---

3. ---

4. ---

5. __ (Largest)

Mechanic’s Tip: To compare fractions easily, find a common denominator (like 8) for all of them first.

Section 2: At the Fuel Pump (Decimals & Multiplication)

Calculations at the pump are essential for tracking a vehicle's efficiency and cost.

Task: Calculate the total cost for the fuel needed. Round your answer to the nearest cent.

Section 3: The Engine Oil Log (Addition & Volume)

Engines need the right amount of oil to run smoothly. If you put in too much or too little, you can damage the engine.

Task: A shop has a 20-liter barrel of oil. Calculate how much oil remains in the barrel after each job.

Starting Balance: 20.0 Liters

1. Job 1: Used 4.5 liters for a sedan. Remaining oil: __

2. Job 2: Used 6.2 liters for a truck. Remaining oil: __

3. Job 3: Used 5.8 liters for an SUV. Remaining oil: __

4. Job 4: Used 2.1 liters for a small tractor. Remaining oil: __

Final Question: Is there enough oil left in the barrel to perform one more oil change that requires 3.0 liters? (Yes/No): __

Section 4: Tire Pressure & Safety (Logic & Comparison)

Tire pressure is measured in PSI (Pounds per Square Inch). Proper pressure ensures safety and better fuel mileage.

Task: Look at the chart below. Determine if the tire is Under-inflated, Correct, or Over-inflated based on the Recommended PSI.

Section 5: The Repair Bill (Multi-Step Problems)

As a lead mechanic, you need to provide customers with an accurate estimate of their bill.

Scenario: A customer needs their brakes fixed.

• Parts: $145.50
• Labor: $80.00 per hour
• Time: The job takes 3 hours

1. What is the total cost for Labor? __
2. What is the Subtotal (Parts + Labor)? __
3. If there is a 10% Shop Fee added to the Subtotal, how much is the fee? __
4. What is the Grand Total for the customer? __

Challenge: Gear Ratios (Advanced Thinking)

If a small gear with 10 teeth (the driver) turns a large gear with 40 teeth (the follower), the ratio is 1:4. This means for every 4 times the small gear spins, the big gear spins once.

Question: If the driver gear has 12 teeth and the follower gear has 36 teeth:

1. What is the simplified gear ratio? __
2. If the small gear spins 30 times, how many times will the large gear spin? __

Answer Key

Section 1: The Tool Box

1. 1/4" (2/8)
2. 3/8"
3. 1/2" (4/8)
4. 5/8"
5. 3/4" (6/8)

Section 2: At the Fuel Pump

• Pickup Truck: $129.20
• Delivery Van: $162.80
• Motorcycle: $19.80
• SUV: $116.25
• Tow Truck: $240.00

Section 3: The Engine Oil Log

1. 15.5 L
2. 9.3 L
3. 3.5 L
4. 1.4 L
   • Final Question: No (Only 1.4 L left).

Section 4: Tire Pressure

• Front Right: Correct
• Rear Left: Over-inflated
• Rear Right: Correct
• Spare Tire: Under-inflated

Section 5: The Repair Bill

1. $240.00 ($80 x 3)
2. $385.50 ($145.50 + $240.00)
3. $38.55 ($385.50 x 0.10)
4. $424.05 ($385.50 + $38.55)

Challenge: Gear Ratios

1. 1:3
2. 10 times (30 ÷ 3)