Solve Conversion Problems

In this activity, remember that milli- means 1000th and centi- means 100th.

Also, kilo means 1000.

This means that:

1 mm = 0.001 m

1 ml = 0.001 l

1 mg = 0.001 g

1 cm = 0.01 m

1 cl = 0.01 l

1 g = 0.001 kg

When problems involve mixed units of measurement, always convert them to work in just one unit.

Often, it is easier to work with the smaller unit of measurement and then convert back at the end if the question asks for the answer in the larger unit of measurement.

Example 1

Jack pours out 2 litres of water into a pan and then removes 32 ml.

How much is left in the pan, in litres?

Answer

Let's work in millilitres.

2000 ml - 32 ml = 1968 ml

Convert back to litres by dividing by 1000.

1.968 l is left in the pan.

Example 2

Ann joins a 52 cm pipe, end to end, to one that is 2.5 m long.

How long are both pipes together in m?

Answer

Work in cm.

52 cm + 250 cm = 302 cm

Convert back to m by dividing by 100.

The pipe is 3.02 m long.

Does that make sense?

Let's try some questions on this now.

There's a lot of stuff to remember on this page, so feel free to look back at it whenever you want to - just click on the red help button on the screen.