Solved Exercises on Liquid Volume Practice in Grade 3

Master liquid volume measurement: comparing capacities, adding/subtracting volumes, converting units, and solving word problems through these 5 detailed exercises.

Solution: Exercises 1 to 3
1 Comparing liquid volumes
Exercise 1
Which container holds more water?
Container A has 3 liters and Container B has 2,500 milliliters.
Definition:

Liquid volume: The amount of space a liquid takes up, measured in liters (L) and milliliters (mL)

Comparison method:
  1. Convert both measurements to the same unit (liters or milliliters)
  2. Compare the numerical values
  3. Determine which is greater
Container A
3 L
Container B
2,500 mL
Comparison
3 L > 2.5 L
Step 1: Convert to same units

Convert 2,500 mL to liters: 2,500 mL ÷ 1,000 = 2.5 L

Step 2: Compare the values

Container A: 3 L vs Container B: 2.5 L

Step 3: Determine the larger amount

3 L > 2.5 L, so Container A holds more water

Container A (3 L) holds more water than Container B (2,500 mL)
Final answer:

Container A holds more water because 3 L > 2.5 L

Applied rules:

• Conversion: 1 L = 1,000 mL

• Comparison: Convert to same unit before comparing

• Measurement: Larger number means more volume

2 Adding liquid volumes
Exercise 2
Sarah poured 1 liter of juice into a pitcher. Then she added 750 milliliters more. How much juice is in the pitcher altogether?
Definition:

Addition of volumes: Combine amounts of liquid to find the total capacity

Initial
1 L
Added
750 mL
Total
1.75 L
Step 1: Convert to same units

Convert 1 L to milliliters: 1 L = 1,000 mL

Step 2: Add the volumes

1,000 mL + 750 mL = 1,750 mL

Step 3: Convert back to mixed units

1,750 mL = 1 L 750 mL or 1.75 L

There are 1,750 mL (or 1.75 L) of juice in the pitcher
Final answer:

There are 1.75 liters of juice in the pitcher

Applied rules:

• Conversion: 1 L = 1,000 mL

• Addition: Add volumes when combining liquids

• Units: Always convert to same unit before calculating

3 Measuring capacity
Exercise 3
A water bottle holds 500 milliliters. How many bottles are needed to fill a 2-liter container?
Definition:

Capacity: The maximum amount a container can hold

Container
2 L
Bottle
500 mL
Number
4 bottles
Step 1: Convert to same units

Convert 2 L to milliliters: 2 L = 2,000 mL

Step 2: Divide total capacity by bottle size

2,000 mL ÷ 500 mL = 4 bottles

Step 3: Verify the answer

4 bottles × 500 mL = 2,000 mL = 2 L ✓

4 bottles are needed to fill the 2-liter container
Final answer:

4 bottles are needed to fill the 2-liter container

Applied rules:

• Division: Divide total capacity by individual container size

• Conversion: Ensure same units before dividing

• Verification: Multiply to check the answer

Volume Units and Conversion Rules
1 L = 1,000 mL
Liquid Volume Conversion
Liter to Milliliter
L × 1,000 = mL
Multiply by 1,000
Milliliter to Liter
mL ÷ 1,000 = L
Divide by 1,000
Mixed Units
1.5 L = 1,500 mL
Combine whole and fractional parts
Key definitions:

Liter (L): Standard unit for measuring large liquid volumes

Milliliter (mL): Smaller unit for measuring small liquid volumes

Capacity: Maximum amount a container can hold

Measurement methodology:
  1. Identify units: Recognize liters and milliliters in the problem
  2. Convert units: Change all measurements to the same unit
  3. Perform operation: Add, subtract, or compare as needed
  4. Express answer: In the required unit
Tip 1: Remember: 1 liter is the same as 1,000 milliliters.
Tip 2: A regular water bottle usually holds about 500 mL.
Tip 3: Always convert to the same unit before doing calculations.
Tip 4: Check if your answer makes sense in real life.
Common volumes: Teaspoon ≈ 5 mL, Cup ≈ 240 mL, Bottle ≈ 500 mL, Jug ≈ 1-2 L.
Estimation: Use familiar containers to estimate volumes.
Conversion facts to know:

• 1 L = 1,000 mL

• 2 L = 2,000 mL

• 500 mL = 0.5 L

• 250 mL = 0.25 L

• 750 mL = 0.75 L

Solution: Exercises 4 to 5
4 Subtracting liquid volumes
Exercise 4
A fish tank had 15 liters of water. After cleaning, 4,000 milliliters were removed. How much water remains in the tank?
Definition:

Subtraction of volumes: Finding remaining liquid after some is removed

Initial
15 L
Removed
4,000 mL
Remaining
11 L
Step 1: Convert to same units

Convert 4,000 mL to liters: 4,000 mL ÷ 1,000 = 4 L

Step 2: Subtract the removed amount

15 L - 4 L = 11 L

Step 3: Verify the result

11 L + 4 L = 15 L ✓

11 liters of water remain in the tank
Final answer:

11 liters of water remain in the tank

Applied rules:

• Conversion: Change all units to same measurement

• Subtraction: Take away the removed amount from initial

• Verification: Add remaining and removed to check initial

5 Word problem with mixed operations
Exercise 5
A restaurant has 3 containers of soup. The first has 2.5 liters, the second has 1,800 milliliters, and the third has 1.2 liters. If they serve 2,000 milliliters, how much soup remains?
Definition:

Multi-step volume problems: Problems requiring addition, conversion, and subtraction

Total
5.5 L
Served
2 L
Remaining
3.5 L
Step 1: Convert all to same unit (liters)

Container 1: 2.5 L, Container 2: 1,800 mL = 1.8 L, Container 3: 1.2 L

Step 2: Add all volumes

Total: 2.5 L + 1.8 L + 1.2 L = 5.5 L

Step 3: Convert served amount to liters

2,000 mL = 2 L

Step 4: Subtract served from total

5.5 L - 2 L = 3.5 L

3.5 liters of soup remain
Final answer:

3.5 liters of soup remain

Applied rules:

• Organization: List all quantities before calculating

• Conversion: Convert all measurements to same unit

• Operations: Perform addition then subtraction

Volume Measurement Laws, Methods, and Definitions
1 L = 1,000 mL
Volume Conversion
Key definitions:

Liquid Volume: The amount of space occupied by a liquid

Capacity: The maximum volume a container can hold

Measurement: Determining how much liquid is present

Complete methodology:
  1. Read the problem: Identify initial and final volumes
  2. Identify units: Note liters and milliliters
  3. Convert units: Change to same measurement system
  4. Perform calculation: Add, subtract, or multiply as needed
  5. Verify answer: Check if result makes sense
Tip 1: Use a conversion chart when learning: 1 L = 1,000 mL.
Tip 2: Draw pictures to visualize the problem.
Tip 3: Estimate first, then calculate precisely.
Tip 4: Always check if your answer is reasonable.
Common errors: Forgetting to convert units, miscalculating conversions, not checking work.
Real-world applications: Cooking, science experiments, filling containers, measuring medicine.
Volume formulas to know:

• Total volume = Sum of individual volumes

• Remaining volume = Initial volume - Removed volume

• Number of containers = Total volume ÷ Individual capacity

• Conversion: L to mL multiply by 1,000; mL to L divide by 1,000

Volume Visualization: Capacity Comparison
Exercise 6: Volume Relationships
Different containers and their typical capacities:
Small cup: 250 mL
Water bottle: 500 mL
Large jug: 2 L
Fish tank: 10 L

Analysis: The chart shows the relationship between different liquid volume measurements and common containers.

  • Small cup = 250 mL = 0.25 L
  • Water bottle = 500 mL = 0.5 L
  • Large jug = 2 L = 2,000 mL
  • Fish tank = 10 L = 10,000 mL

Questions & Answers

Question: I don't understand how to change liters to milliliters. Can you explain the difference between liters and milliliters?

Answer: Great question! Think of liters and milliliters like dollars and cents:

  • A liter (L) is a big unit for measuring larger amounts of liquid, like a big bottle of juice.
  • A milliliter (mL) is a tiny unit for measuring small amounts of liquid, like medicine.

The key relationship is: 1 L = 1,000 mL. This means 1 liter contains 1,000 milliliters!

To convert liters to milliliters: Multiply by 1,000
Example: 3 L = 3 × 1,000 = 3,000 mL

To convert milliliters to liters: Divide by 1,000
Example: 2,500 mL = 2,500 ÷ 1,000 = 2.5 L

Question: When I have to add 2 L and 500 mL, should I change both to liters or both to milliliters?

Answer: You can choose either approach, but here's how both work:

  • Method 1: Convert everything to milliliters (larger numbers but easier addition)
    2 L = 2,000 mL, so 2,000 mL + 500 mL = 2,500 mL
  • Method 2: Convert everything to liters (smaller numbers but decimal addition)
    500 mL = 0.5 L, so 2 L + 0.5 L = 2.5 L

Both answers are correct! 2,500 mL = 2.5 L. Choose the method that feels easier for you.

Tip: When adding, I often recommend converting to the smaller unit (mL) to avoid decimals.

Question: How can I remember that 1,000 milliliters equals 1 liter?

Answer: Here are several memory tricks for the 1 L = 1,000 mL relationship:

  • Counting trick: Count to 1,000 and say "mL" - it takes longer than saying "1 L", showing that mL is smaller
  • Size comparison: Think of a large milk carton (1 L) vs. a medicine dropper (1 mL)
  • Word connection: "Milli" means thousandth, so 1,000 mL make 1 L

Practice with real objects: a water bottle (500 mL) needs to be filled twice to make 1 L.

Create a visual: Draw a 1 L container and show it divided into 1,000 tiny sections.