Measurement Conversion Word Problems
Measurement conversion word problems require you to convert between units before solving. In Class 3, you work with conversions involving length (m and cm), weight (kg and g), and capacity (L and mL).
The key to solving these problems is to convert all measurements to the same unit before adding, subtracting, or comparing.
What is Measurement Conversion Word Problems - Class 3 Maths (Measurement (Grade 3))?
Key Conversions:
1 m = 100 cm
1 km = 1000 m
1 kg = 1000 g
1 L = 1000 mL
To convert larger to smaller: Multiply (e.g., 3 kg = 3 × 1000 = 3000 g)
To convert smaller to larger: Divide (e.g., 2500 g = 2500 ÷ 1000 = 2 kg 500 g)
Types and Properties
Types of Conversion Word Problems
1. Length Conversions — m ↔ cm, km ↔ m
2. Weight Conversions — kg ↔ g
3. Capacity Conversions — L ↔ mL
4. Mixed-Unit Addition/Subtraction — Convert first, then calculate.
Solved Examples
Example 1: Example 1: Length – m and cm
Question: Aman has a rope of 2 m 30 cm. Ria has a rope of 175 cm. Who has the longer rope? By how much?
Think:
- Convert: 2 m 30 cm = 230 cm
- Compare: 230 cm > 175 cm
- Difference: 230 − 175 = 55 cm
Answer: Aman has the longer rope, by 55 cm.
Example 2: Example 2: Weight – kg and g
Question: Priya buys 1 kg 200 g of apples and 800 g of grapes. What is the total weight?
Think:
- Convert: 1 kg 200 g = 1200 g
- Total: 1200 + 800 = 2000 g
- Convert back: 2000 g = 2 kg
Answer: Total weight = 2 kg.
Example 3: Example 3: Capacity – L and mL
Question: A jug holds 2 L of water. Dev pours out 750 mL. How much water is left?
Think:
- Convert: 2 L = 2000 mL
- Subtract: 2000 − 750 = 1250 mL
- Convert: 1250 mL = 1 L 250 mL
Answer: 1 L 250 mL of water is left.
Example 4: Example 4: Adding Mixed Units (Length)
Question: A table is 1 m 45 cm long. A chair is 65 cm long. What is the total length?
Think:
- 1 m 45 cm = 145 cm
- Total = 145 + 65 = 210 cm = 2 m 10 cm
Answer: Total length = 2 m 10 cm.
Example 5: Example 5: Subtracting Weights
Question: A bag of flour weighs 5 kg. Meera uses 2 kg 350 g. How much flour is left?
Think:
- 5 kg = 5000 g
- 2 kg 350 g = 2350 g
- Remaining: 5000 − 2350 = 2650 g = 2 kg 650 g
Answer: 2 kg 650 g of flour is left.
Example 6: Example 6: Comparing Capacities
Question: Bottle A holds 1 L 500 mL. Bottle B holds 1750 mL. Which bottle holds more?
Think:
- Bottle A: 1 L 500 mL = 1500 mL
- Bottle B: 1750 mL
- 1750 > 1500
Answer: Bottle B holds more, by 250 mL.
Example 7: Example 7: Multi-Step Weight Problem
Question: Aditi buys 3 packets of biscuits. Each packet weighs 250 g. What is the total weight in kg and g?
Think:
- Total = 3 × 250 = 750 g
- 750 g < 1000 g, so it is 0 kg 750 g
Answer: Total weight = 750 g.
Example 8: Example 8: Distance Problem
Question: Rahul walks 500 m to school and 300 m to the park after school. What is the total distance in metres? Convert to km.
Think:
- Total: 500 + 300 = 800 m
- 800 m < 1000 m, so it is less than 1 km
Answer: Total distance = 800 m.
Example 9: Example 9: Sharing Equally
Question: Kavi has 2 L of juice. He pours it equally into 4 glasses. How much juice is in each glass?
Think:
- 2 L = 2000 mL
- Each glass = 2000 ÷ 4 = 500 mL
Answer: Each glass has 500 mL of juice.
Example 10: Example 10: Combined Problem
Question: Neha buys 1 kg 500 g of rice and 2 kg 750 g of wheat. What is the total weight?
Think:
- Rice: 1500 g, Wheat: 2750 g
- Total: 1500 + 2750 = 4250 g
- Convert: 4250 g = 4 kg 250 g
Answer: Total weight = 4 kg 250 g.
Real-World Applications
Where Do We Use Measurement Conversions?
- Cooking: Recipes use kg, g, L, and mL. You often need to double or halve amounts.
- Shopping: Comparing prices of different-sized packets (500 g vs 1 kg).
- Travel: Distances in km and m.
- Health: Measuring weight in kg and g.
- Science: Measuring liquids in L and mL for experiments.
Key Points to Remember
- 1 m = 100 cm, 1 km = 1000 m
- 1 kg = 1000 g
- 1 L = 1000 mL
- Convert to the same unit before adding, subtracting, or comparing.
- Larger to smaller: multiply. Smaller to larger: divide.
- Always convert back to mixed units (kg and g) in the final answer when possible.
Practice Problems
- Convert 3 m 50 cm to cm.
- Add: 2 kg 400 g + 1 kg 800 g.
- A bottle has 1 L 200 mL. Another has 900 mL. What is the total?
- Subtract: 5 m − 2 m 60 cm.
- Which is heavier: 3 kg 100 g or 2950 g?
- Ria has 3 ribbons each 75 cm long. What is the total length in m and cm?
- A tank has 10 L of water. 3 L 500 mL is used. How much is left?
Frequently Asked Questions
Q1. Why do I need to convert before adding?
You cannot add different units directly. For example, 2 kg + 500 g cannot be added until you convert to the same unit: 2000 g + 500 g = 2500 g.
Q2. How do I convert kg to g?
Multiply by 1000. For example, 3 kg = 3 × 1000 = 3000 g.
Q3. How do I convert g to kg?
Divide by 1000. For example, 4500 g = 4500 ÷ 1000 = 4 kg 500 g.
Q4. What is the difference between m and cm?
1 metre = 100 centimetres. Metres are used for larger measurements (room, field) and centimetres for smaller ones (pencil, book).
Q5. What is the difference between L and mL?
1 litre = 1000 millilitres. Litres are used for large quantities (bucket, tank) and millilitres for small quantities (medicine, drops).
Q6. How do I write the answer in mixed units?
Divide by the conversion factor. The quotient is the larger unit and the remainder is the smaller unit. For example, 3250 g: 3250 ÷ 1000 = 3 remainder 250, so 3 kg 250 g.
Q7. Is 1500 mL the same as 1 L 500 mL?
Yes. 1500 mL = 1000 mL + 500 mL = 1 L 500 mL.
Q8. What units of length are used in Class 3?
Class 3 mainly uses centimetres (cm) and metres (m). Kilometres (km) are introduced for longer distances.
