MEASURES AND TIME

Metric Units

Learn the reliable method for metric units, then apply it to 11+ exam-style questions.

1 · WHAT YOU NEED TO KNOW

The idea

Metric Units questions combine accurate calculation with careful use of units.

Picture itConnect the number to its unit and scale
2 · THE METHOD

Follow these steps

  1. Read every unit before calculating.
  2. Convert all values to the same unit.
  3. Complete the operation, then give the answer in the unit requested.
3 · WORKED EXAMPLES

See the method in action

Example 1

What is the difference, in g, between 2 kg and 2,250 g?

Conversion bridgeConvert both amounts to g first2 kg2250 g
  1. 2 kg = 2,000 g.
  2. The difference is 2,250 − 2,000 = 250 g.
Answer: 250 g
Example 2

A café needs 11 litres of juice. There is 9 litres and 125 ml available. How much more is needed, in ml?

11 litres target9 litres 125 ml
  1. First convert both quantities to ml: the target is 11,000 and the current quantity is 9,125.
  2. Then subtract 9,125 from 11,000 to get 1,875 ml.
Answer: 1,875 ml
4 · ELEVENSPRINT TIP

A useful shortcut

Convert first, calculate second.

5 · COMMON MISTAKES

Watch out for these

Using the wrong conversion factor

Use 1,000 between kg and g, litres and ml, and km and m; use 100 between m and cm.

6 · TRY IT YOURSELF

Three fresh questions

Ready to check the method? You will get three fresh, validated questions.