Class 4 Maths Chapter 8 Weigh it, Pour it – Revision Notes

Chapter 8, Weigh it, Pour it, covers two related measurement ideas: weight (how heavy something is, measured in grams and kilograms) and capacity (how much liquid something can hold, measured in millilitres and litres). Both use the same style of conversion as length, so once one is clear, the other follows easily.

Last Updated: September 23, 2026

Key Concepts

Weight

Weight tells us how heavy an object is. Very light objects (a key, a pencil, a few grains of rice) are measured in grams (g), while heavier objects (a bag of rice, a person, a sack of flour) are measured in kilograms (kg).

1 kilogram = 1,000 grams

Capacity

Capacity tells us how much liquid a container can hold. Small amounts (a spoon of syrup, a cup of milk) are measured in millilitres (ml), while larger amounts (a bucket of water, a can of oil) are measured in litres (l).

1 litre = 1,000 millilitres

Measuring tools

Weight is measured using a weighing scale/balance. Capacity is measured using a measuring cylinder, jar, or jug with marked levels.

Quick Recap

• 1 kilogram = 1,000 grams.
• 1 litre = 1,000 millilitres.
• Convert quantities to the same unit before adding or subtracting weights or volumes.
• Choose the unit that fits the size of the object — grams for a key, kilograms for a sack of rice; millilitres for a spoon of oil, litres for a bucket of water.
• To go from kg to g, or l to ml, multiply by 1,000. To go the other way, divide by 1,000.

Worked Examples

Example 1: A bag of sugar weighs 2 kg 250 g. What is this in grams?
Solution: 2 kg = 2,000 g. Total = 2,000 g + 250 g = 2,250 g.

Example 2: A jug holds 1 litre 500 ml of juice. If 750 ml is poured out, how much juice is left?
Solution: 1 l 500 ml = 1,500 ml. Remaining = 1,500 ml − 750 ml = 750 ml.

Example 3: Three packets of flour weigh 500 g, 750 g and 1 kg. What is their combined weight in kilograms?
Solution: 500 g + 750 g + 1,000 g = 2,250 g = 2.25 kg (2 kg 250 g).

Common Mistake to Avoid

A common mistake is adding quantities given in different units without converting them first — for example, adding “2 kg + 500 g” directly as “2.500” without realising the units must first be matched (either both in grams, or both in kilograms). Always convert every quantity to the same unit before doing the arithmetic, whether for weight or capacity.

Practice Questions to Try

1. Convert 3 kg 400 g into grams.
2. A milk can holds 5 litres. If 1,250 ml has been used, how much milk is left, in litres and millilitres?
3. Which is heavier: 750 g of rice or half a kilogram of rice?
4. Arrange in increasing order: 1,200 ml, 1 l, 900 ml.

Answers: 1. 3,400 g   2. 5 l = 5,000 ml; 5,000 − 1,250 = 3,750 ml = 3 l 750 ml   3. 750 g is heavier (half a kg = 500 g)   4. 900 ml < 1 l (1,000 ml) < 1,200 ml

Step-by-Step Method for Any Weight/Capacity Problem

Step 1: Note the units given in the question (g/kg for weight, ml/l for capacity).
Step 2: If the units are different, convert everything to the smaller unit first (grams or millilitres) — this avoids decimals in most Class 4 problems.
Step 3: Do the addition, subtraction, or comparison.
Step 4: Convert the final answer back to the bigger unit if the question asks for kg or litres.

More Worked Examples

Example 4: A shopkeeper has 4 kg of rice. He sells 1 kg 600 g in the morning and 950 g in the evening. How much rice is left?
Solution: Total sold = 1,600 g + 950 g = 2,550 g. Rice left = 4,000 g − 2,550 g = 1,450 g, i.e. 1 kg 450 g.

Example 5: A bottle can hold 2 litres. How many 250 ml glasses can be completely filled from it?
Solution: 2 litres = 2,000 ml. 2,000 ÷ 250 = 8 glasses.

Example 6: Which weighs more: 1 kg 50 g of flour, or 1,200 g of sugar?
Solution: 1 kg 50 g = 1,050 g. Since 1,200 g > 1,050 g, the sugar is heavier.

Real-Life Connections

Weight and capacity appear constantly outside the classroom — reading the net weight on a packet of biscuits, checking how much milk is left in a 1-litre packet, or figuring out how many 200 g cups of flour are needed for a recipe that calls for 1 kg. Practising with kitchen scales and measuring jugs at home turns this chapter’s ideas from abstract numbers into something children can actually see and touch.

Frequently Asked Questions

How do I decide whether to use grams or kilograms for an object?
Think about how heavy the object roughly feels — very light objects like a key or a spoon are measured in grams, while heavier ones like a bag of rice or a person’s weight are measured in kilograms.

Is capacity the same as volume?
At this level, capacity simply means how much liquid a container can hold, measured in millilitres and litres — that is enough for Chapter 8; the more general idea of volume for solid shapes comes in later classes.

What household tools can be used to practise this chapter at home?
A kitchen weighing scale for weight, and a measuring cup or bottle with ml/litre markings for capacity — both let a child compare their real-world measurement against the numbers in the textbook.

Why convert to the smaller unit before adding, instead of the bigger unit?
Converting to the smaller unit (grams or millilitres) avoids fractions or decimals in most problems at this level, making the addition or subtraction simpler and less error-prone.

Is 1,000 always the conversion number for weight and capacity, like it is for length (m to km)?
Yes — kg to g and litres to ml both use 1,000, exactly like m to km, which makes it easier to remember all three conversions using the same “1,000 rule” once a student is confident with one of them.

Full walkthrough: Chapter 8 Solutions · Extra Questions.

Written by Satish

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