5.1.8 Prefixes in the Metric System

By now, you’ll probably have guessed the pattern of units. Working from liters, the two most common multiples are the centiliter (cl), which is one-hundredth of a liter (just as 1 centimeter is one-hundredth of a meter), and the milliliter (ml), which is one-thousandth of a liter.

Try the next activity to see how these prefixes work.

Activity symbol Activity: A Dose of Medicine

A new bottle of medicine contains 14 cl. The dose is 5 ml. How many doses can be given from this bottle?

Hint symbol


How would you describe, perhaps to a friend, how to convert between milliliters, centiliters, and liters? Use this diagram if it helps.

Solution symbol


To find the number of doses, the volume of the bottle and the dose need to be in the same units. There are 10 ml in 1 cl. Therefore, 14 cl equation left hand side equals right hand side 14 multiplication 10 ml equals 140 ml.

So, the number of doses in the bottle is 140 division five, or 28 doses.

5.1.7 Length in the Metric System

5.2 Negative Numbers