Sita wants to buy ribbon for her craft project. The shopkeeper asks, "How much ribbon do you need?" Sita says, "About this much," and shows with her hands.
But "this much" is not exact! We need a proper way to tell how long, how heavy, or how much something is. That is why we use measurement.
We use centimetres and metres for length, kilograms and grams for weight, and litres and millilitres for liquids.
Using a Ruler
A ruler helps us measure how long something is. The small lines on a ruler show centimetres (cm). To measure, place the object at the 0 mark and read the number at the other end.
A pencil that goes from 0 to 15 on the ruler is 15 cm long.
Think about it: Your thumb is about 1 cm wide. How many thumb-widths long is your eraser?
Comparing Lengths
We can compare two things and say which is longer and which is shorter.
A cricket bat is longer than a pencil. A matchstick is shorter than a spoon.
Centimetre and Metre
For small things (pencil, book, hand), we use centimetres (cm).
For bigger things (room, playground, road), we use metres (m).
1 metre = 100 centimetres
A classroom door is about 2 metres tall. A new pencil is about 18 centimetres long.
Heavier and Lighter
Some things are heavy and some are light. A watermelon is heavier than an apple. A feather is lighter than a book.
Kilogram and Gram
We measure weight in kilograms (kg) and grams (g).
1 kilogram = 1000 grams
Heavy things like rice, sugar and vegetables are measured in kg. Light things like a biscuit or a small packet of spice are measured in grams.
Think about it: A packet of chips weighs about 30 g. A bag of rice weighs about 5 kg. Which is heavier?
Litre and Millilitre
We measure liquids like water, milk and oil in litres (L) and millilitres (mL).
1 litre = 1000 millilitres
A big water bottle holds about 1 litre. A small medicine spoon holds about 5 mL.
Choosing the Right Unit
| What to Measure | Use This Unit | Example |
|---|---|---|
| Length of a pencil | cm | 18 cm |
| Length of a playground | m | 50 m |
| Weight of a mango | g | 200 g |
| Weight of a suitcase | kg | 12 kg |
| Water in a glass | mL | 250 mL |
| Milk in a bucket | L | 5 L |
| Word | Meaning |
|---|---|
| Centimetre (cm) | A small unit for measuring length |
| Metre (m) | A bigger unit for measuring length; 1 m = 100 cm |
| Kilogram (kg) | A unit for measuring weight of heavy things |
| Gram (g) | A unit for measuring weight of light things; 1 kg = 1000 g |
| Litre (L) | A unit for measuring liquids |
| Millilitre (mL) | A smaller unit for measuring liquids; 1 L = 1000 mL |
Which unit would you use to measure the length of a cricket pitch?
A cricket pitch is long, so we use metres (m). A cricket pitch is about 20 m long.
Rani bought 2 kg of potatoes and 500 g of tomatoes. Which is heavier?
2 kg = 2000 g. Since 2000 g > 500 g, the potatoes are heavier.
A jug holds 2 litres of water. How many millilitres is that?
1 L = 1000 mL, so 2 L = 2 × 1000 = 2000 mL.
A. Fill in the Blanks
B. Multiple Choice Questions
C. Choose the Right Unit (cm, m, g, kg, mL, L)
D. Short Answer
Measure Around You: Use a ruler or a measuring tape to measure 5 things at home. Write the object name and its length below.
| Object | Length (in cm or m) |
|---|---|
Which object is the longest? __________________ Which is the shortest? __________________