Learning Objectives
- Convert between kilometres and metres, and metres and centimetres.
- Convert between kilograms and grams.
- Convert between litres and millilitres.
- Add and subtract measurements with different units.
- Solve word problems involving measurement conversions.
Let Us Begin!
In Class 3, you learned about metres, kilograms, and litres. Now in Class 4, we will learn to convert between bigger and smaller units. This is very useful in daily life!
When your mother buys 1 kg 250 g of rice and 750 g of dal, how much does she carry in total? When you travel 2 km 300 m to school and then 500 m to the market, what is the total distance? Let us find out!
Conversion Rules
| Measurement | Conversion |
|---|
| Length | 1 km = 1000 m, 1 m = 100 cm |
| Weight | 1 kg = 1000 g |
| Capacity | 1 L = 1000 mL |
To convert from a bigger unit to a smaller unit, multiply. To convert from a smaller unit to a bigger unit, divide.
[Image: Metric Conversion Chart — Length (mm →×10→ cm →×100→ m →×1000→ km), Weight (g →×1000→ kg), Capacity (mL →×1000→ L). Directional arrows showing multiply/divide between units.]
Converting Length
Example 1: Convert 3 km 450 m to metres.
3 km = 3 × 1000 = 3000 m. Total = 3000 + 450 = 3450 m.
Example 2: Convert 5200 m to km and m.
5200 ÷ 1000 = 5 km and 200 m. Answer: 5 km 200 m.
Example 3: Convert 4 m 35 cm to centimetres.
4 m = 4 × 100 = 400 cm. Total = 400 + 35 = 435 cm.
Think: The distance from your home to school is 1 km 800 m. How many metres is that?
Converting Weight
Example 4: Convert 2 kg 750 g to grams.
2 kg = 2 × 1000 = 2000 g. Total = 2000 + 750 = 2750 g.
Example 5: Convert 4500 g to kg and g.
4500 ÷ 1000 = 4 kg and 500 g. Answer: 4 kg 500 g.
Converting Capacity
Example 6: Convert 3 L 200 mL to millilitres.
3 L = 3 × 1000 = 3000 mL. Total = 3000 + 200 = 3200 mL.
Example 7: Convert 6750 mL to litres and millilitres.
6750 ÷ 1000 = 6 L and 750 mL. Answer: 6 L 750 mL.
Adding and Subtracting Measurements
When adding or subtracting, first convert to the same unit, or add/subtract the smaller units and bigger units separately.
Example 8: Add 2 kg 600 g + 1 kg 750 g
Add grams: 600 + 750 = 1350 g = 1 kg 350 g.
Add kilograms: 2 + 1 + 1 (carry) = 4 kg.
Answer: 4 kg 350 g.
Example 9: Subtract 5 km 200 m − 2 km 800 m
We cannot subtract 800 from 200. Borrow 1 km = 1000 m.
Now: 4 km 1200 m − 2 km 800 m = 2 km 400 m.
Key Words
| Word | Meaning |
|---|
| Kilometre (km) | A unit of length equal to 1000 metres |
| Gram (g) | A small unit of weight; 1000 g = 1 kg |
| Millilitre (mL) | A small unit of capacity; 1000 mL = 1 L |
| Convert | To change from one unit to another |
⭐ Key Points to Remember:
- 1 km = 1000 m, 1 m = 100 cm.
- 1 kg = 1000 g, 1 L = 1000 mL.
- Bigger to smaller unit: multiply. Smaller to bigger unit: divide.
- When adding, if the smaller unit exceeds 1000 (or 100 for cm), carry over to the bigger unit.
- When subtracting, borrow from the bigger unit if needed.
Practice Questions
A. Fill in the Blanks
1. 1 km = m
2. 3 kg 200 g = g
3. 5000 mL = L
4. 2 m 50 cm = cm
5. 7250 g = kg g
B. Convert
1. 4 km 300 m = m
2. 8500 m = km m
3. 6 L 450 mL = mL
4. 3200 g = kg g
C. Add or Subtract
1. 3 km 500 m + 2 km 700 m =
2. 5 kg 300 g − 2 kg 800 g =
3. 4 L 250 mL + 3 L 900 mL =
4. 7 m 20 cm − 3 m 65 cm =
D. Multiple Choice Questions
1. How many grams are there in 5 kg?
(a) 500 g(b) 5000 g(c) 50 g(d) 50000 g
2. 3 km 750 m is the same as:
(a) 3750 m(b) 3075 m(c) 37500 m(d) 375 m
3. 2 L 500 mL + 1 L 700 mL = ?
(a) 3 L 200 mL(b) 4 L 200 mL(c) 3 L 1200 mL(d) 4 L 100 mL
E. Word Problems
1. Aman walks 1 km 600 m to school and 850 m to the library after school. What is the total distance he walks?
2. A shopkeeper has 10 kg of sugar. He sells 3 kg 400 g to one customer and 2 kg 750 g to another. How much sugar is left?
3. A water tank holds 8 L of water. If 2 L 350 mL is used for cooking and 1 L 500 mL for drinking, how much water is left in the tank?
🎨 Fun Activity — Measurement in My Kitchen
Go to your kitchen and find 5 items. Write down their weight or capacity as shown on the packet. Then convert to the smaller unit.
| Item | Weight / Capacity | Converted (g or mL) |
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