Capacity Measurements
Primary 4 · Mathematics
Capacity Measurements
Lesson 2 of 4
20 min
Let's begin
Keza has a cough. At the health centre, the nurse gives her a small bottle of syrup. "Take 5 mL every morning," the nurse says. She gives Keza a tiny spoon.
"What is mL?" Keza asks. A litre is far too much for one spoonful of medicine!
Today you will meet the small units and the big units of capacity, and learn how to change from one to another.
A millilitre (mL) is a very small amount of liquid, about 20 drops of water. We use it for medicine, perfume and small drinks.
1 L = 1 000 mL
This means you would fill a 1 mL dropper 1 000 times to fill a 1 L bottle. Look how many times each container must be filled to make 1 L:
| Container | Holds | Fills needed to make 1 L |
|---|---|---|
| medicine dropper | 1 mL | 1 000 |
| medicine spoon | 5 mL | 200 |
| small cup | 250 mL | 4 |
| water bottle | 500 mL | 2 |
There are seven metric units of capacity. Each unit is 10 times the unit just below it.
In daily life we use L and mL most. Big water tanks are sometimes measured in kL. Some drink labels use cL: 50 cL is the same as 500 mL.
Count the steps down the ladder. Each step is × 10.
Worked example 1
3 L = ? mL
Step 1 From L to mL is 3 steps down: × 10 × 10 × 10 = × 1 000.
Step 2 3 × 1 000 = 3 000. So 3 L = 3 000 mL.
Worked example 2
4 L = ? cL. That is 2 steps down, so × 100. 4 × 100 = 400 cL.
Worked example 3
6 000 mL = ? L. 6 000 ÷ 1 000 = 6. So 6 000 mL = 6 L.
Worked example 4
2 500 mL = ? L. 2 500 ÷ 1 000 = 2.5. So 2 500 mL = 2.5 L. You can also say 2 L 500 mL.
Worked example 5
750 mL = ? L. 750 ÷ 1 000 = 0.75 L. Less than 1 000 mL is always less than 1 L.
3 L 250 mL = 3 000 mL + 250 mL = 3 250 mL.
Careful! 4 L 50 mL is 4 050 mL, not 4 500 mL. The 50 mL needs a 0 in front of it, because there are no hundreds of mL.
Tip
Down the ladder, multiply. Up the ladder, divide. Count the steps: 1 step is 10, 2 steps is 100, 3 steps is 1 000. L to mL is 3 steps, so 1 L = 1 000 mL.
Work each one in your exercise book first. Then tap Show answer to check.
5 L = ___ mL
Answer: 5 000 mL, because 5 × 1 000 = 5 000.
8 000 mL = ___ L
Answer: 8 L, because 8 000 ÷ 1 000 = 8.
2 L 300 mL = ___ mL
Answer: 2 300 mL. 2 000 mL + 300 mL = 2 300 mL.
1 500 mL = ___ L
Answer: 1.5 L, because 1 500 ÷ 1 000 = 1.5.
How many 250 mL cups can you fill from a 2 L bottle of juice?
Answer: 8 cups. 2 L = 2 000 mL, and 2 000 ÷ 250 = 8.
What you learned today
Sources and credits
The full capacity ladder from kilolitre to millilitre, the stories, Rwandan examples, drawings and practice questions were written by Ganzaa.
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