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Metric Units

Metric Units

The three common metric units are metre for length, litre for capacity and gram for mass.

Metric units are based on powers of 10, and the metric units (metre, gram, litre) are prefixed to indicate which power of 10 is being used:

milli means a thousandth (`frac(1)(1000)`)

centi means a hundredth (`frac(1)(100)`)

kilo means a thousand

1 kilometre (km) = 1000 metres (m)
1 metre (m) = 100 centimetres (cm)
1 centimetre (mm) = 10 millimetres (mm)

1 tonne (t) = 1000 kilograms (kg)
1 kilogram (kg) = 1000 grams (g)

1 litre (l) = 1000 millilitres (ml)

To convert between amounts, set up a small table for the conversion. On the first line, show the conversion rate. On the second line, put in the value to convert.

Example 1

Dylan is putting up a shelf in an alcove. The alcove measures 1058mm. The shelf is 103cm long. Will the shelf fit?

Change the alcove from mm to cm. Create a small table showing that to get from cm to mm you multiply by 10. As you are starting off with mm, you must divide to get cm.

cm --> mm
1 x 10
1058 ÷ 10 = 105.8 1058

The shelf is smaller than the alcove, so it will fit.

Answer: Yes

Example 2

Mia is measuring out some liquid for a chemistry experiment. She needs 520cm3. What is this in litres?

Change cubic centimetres to millilitres: 520cm3 = 520ml.

litre --> ml
1 x 1000
520 ÷ 1000 = 0.520 520

Create a small table showing litres to millilitres. As you are going from millilitres to litres (the opposite way to the conversion) then it is a division.

Answer: 0.520 litres