CBSE Class 4 · Mathematics
Weigh it, Pour it
Official NCERT chapter from Math-Mela (book code demm1). ExamMaster notes are original teaching at CBSE Class 4 depth.
This lesson follows the official chapter “Weigh it, Pour it” in Math-Mela. The words below are ExamMaster’s teaching, not a paste from the book. Use the NCERT chapter for the classroom sequence; use these notes to hold the idea without copying exercises or figures.
- CBSE Class 4
- Easy level
- 8 concepts
11 kilogram and 1 litre are standard units from last year
Kilogram is a standard weight unit. Litre is a standard capacity unit. They are not the same kind of measure.
Writing 1 kg = 1 L without a density-story is a mash of two tests.
Figure. 1 kilogram and 1 litre are last year's standard units. They are the same kind of idea — one agreed house — but they do not measure the same stuff. A bag is not a jug.
How it works
- Hear kilogramA lift / balance unit.
- Hear litreA fill unit.
- Keep them on their own testsDo not trade them as if they were one.
2Weight is a lift-test; capacity is a fill-test
Heavier is more effort or a lower pan. Capacity is how many fills a bottle takes. Two tests, two words.
A bigger bottle can be lighter if it is emptier.
Figure. Weight is a lift-test: which pan goes down. Capacity is a fill-test: how far the water line climbs. Mixing the two tests is how 1 kg and 1 L get treated as the same sentence.
How it works
- To compare weightLift or balance.
- To compare capacityPour and count fills.
- Do not swap the testsHeight is neither.
4A number without a unit is mute
“2” might be 2 kg or 2 L. Say the unit.
Mute numbers cannot be compared.
Figure. A bare 5 does not say whether you lift or pour. Write the unit or the number cannot be used. 5 kg and 5 L are both honest, and they are still different tests.
How it works
- Write the number2.
- Write the unitkg or L.
- Speak bothNever 2 alone.
5Smaller units (grams, millilitres) fill the same houses
1000 g = 1 kg. 1000 ml = 1 L. Smaller units fill the next house the way ones fill tens.
Writing 1000 in the gram house without trading is an unfinished bundle.
Figure. Grams fill the kilogram house: 1000 g is exactly 1 kg, so the two mass bars match. Millilitres fill the litre house: 1000 mL is exactly 1 L. Matching height is the conversion, not a guess.
How it works
- See 1000 of the small unitg or ml.
- Trade for 1 of the large unitkg or L.
- Keep leftover small units0 to 999.
Grams to a kilogram
A shop pile is 1 kg 250 g. How many grams is that in all?
- 1 kg1000 g
- Extra250 g
- Total1250 g
Pro tip. Smaller units fill the kilogram house: 1000 g make 1 kg.
6Estimate, then weigh or pour
Guess “about 2 kg” or “about 3 L”, then use the balance or the measuring jug.
A guess you will not check is not this chapter’s estimate.
Figure. Estimate names a likely house before the instrument speaks. Here a classroom bag looks like 2 kg and the scale reads 1 kg. The guess is allowed; calling the guess the weight is not.
How it works
- Guess in the unit you will useAbout 2 kg.
- Weigh or pourThe instrument.
- CompareClose or far.
7Convert only when two units must meet
Rewrite g as kg only when a sentence has both. 250 g = 0.250 kg if you need kilograms.
Do not convert every label for sport.
Figure. Convert only when two units must sit in one sum. 2 kg becomes 2000 g so it can meet 500 g; then 2000 + 500 = 2500 g. Do not convert a lone 2 kg that is already in the house you were asked for.
How it works
- See two units of one kindg and kg, or ml and L.
- Use 1000 small = 1 largeThe school rate.
- Rewrite only thenOne kind at a time.
8The same water changes shape, not amount
Pour 1 L from a bottle into a wide bowl. The look changes. The amount stays if nothing spilled.
A new shape is not a new litre-count of that water.
Figure. The same 1 L of water changes shape when it is poured. The tall jug and the wide jug are drawn with equal area (narrow 0.16 by 0.64, wide 0.32 by 0.32), so the amount is the same even though the silhouette is not.
How it works
- Fix the water1 L, no spill.
- Change only the containerBowl instead of bottle.
- Keep the amount claimSame water, new shape.
500 g and 500 ml
- Share a numeral, not the same kind of measure
- Are always the same amount of stuff
- Can be added to make 1000 kg
Weight and capacity are two tests.
Notes
- The official chapter title is “Weigh it, Pour it”. Teach the school test for that title, not a contest shortcut.
- If a step needs a later class, stop. The next official chapter will pick it up.
Formulas
- 1000 g = 1 kg.
- 1000 ml = 1 L.
- Weight and capacity are different tests — do not add their numbers.
Recap
Hold these pegs from the official chapter “Weigh it, Pour it”. The wording is ExamMaster’s teaching, not a textbook recap.
- 1 kilogram and 1 litre are standard units from last year
- Kilogram is a standard weight unit. Litre is a standard capacity unit. They are not the same kind of measure.
- Weight is a lift-test; capacity is a fill-test
- Heavier is more effort or a lower pan. Capacity is how many fills a bottle takes. Two tests, two words.
- A packet and a bottle share a number only after units match
- A 500 g packet and a 500 ml bottle share the numeral 500, not the same kind.
- A number without a unit is mute
- “2” might be 2 kg or 2 L. Say the unit.
- Smaller units (grams, millilitres) fill the same houses
- 1000 g = 1 kg. 1000 ml = 1 L. Smaller units fill the next house the way ones fill tens.
- Estimate, then weigh or pour
- Guess “about 2 kg” or “about 3 L”, then use the balance or the measuring jug.
Practise Weigh it, Pour it
Reading is free and needs no account. Practice, mocks and progress live in the app.
- A 4-question practice set that ends the chapter
- 1 quick check with worked explanations
- Timed mocks scored with the real marking scheme
- Readiness tracked per topic, kept on your device