Grade 4 Mathematics Measurement – Capacity Notes
Mathematics — Measurement
Subtopic: Capacity (for age 9)
Learning goal: Learn what capacity means, the common units we use, and how to change between litres and millilitres.
What is capacity?
Capacity is how much a container can hold. We measure capacity for liquids like water, milk, juice and cooking oil.
- Containers: bottles, jerrycans, cups, kettles and tins all have capacity.
- Capacity tells us "how much" liquid fits inside.
Common units
In Kenya we often use:
- Litre (L) — used for big bottles and jerrycans (1 litre = 1 L).
- Millilitre (mL) — used for small bottles and medicine (1000 millilitres = 1 litre).
Remember: 1 L = 1000 mL. So 0.5 L = 500 mL, 2 L = 2000 mL.
Useful examples (everyday)
Sachet / small pack
Water bottle
Jerrycan
Converting between L and mL
To change litres to millilitres, multiply by 1000. To change millilitres to litres, divide by 1000.
Examples:
- 0.5 L = 0.5 × 1000 = 500 mL.
- 3 L = 3 × 1000 = 3000 mL.
- 1500 mL = 1500 ÷ 1000 = 1.5 L.
- 250 mL = 250 ÷ 1000 = 0.25 L.
Short activities (do with a measuring jug)
- Find a 1 L bottle and a 500 mL bottle at home. Pour water from one to the other and watch the levels.
- Use a measuring jug. Fill 3 × 500 mL bottles. How much water did you pour in litres? (3 × 500 = 1500 mL → 1.5 L)
- If a jerrycan has 20 L, how many 1 L bottles will fill it? (Answer: 20 bottles)
Practice questions
- Convert 2500 mL to litres.
- How many millilitres are in 2.75 L?
- If Mama buys 4 bottles of 500 mL milk, how many litres of milk did she buy?
- A small juice pack is 250 mL. How many packs make 1 L?
Show answers
- 2500 mL = 2500 ÷ 1000 = 2.5 L.
- 2.75 L = 2.75 × 1000 = 2750 mL.
- 4 × 500 mL = 2000 mL = 2 L.
- 1 L = 1000 mL. 1000 ÷ 250 = 4 packs.