In order to compare quantities, it is best to express them in the same units.

## Example 10

Three children have just measured their own heights in metric units. Isaac says â€˜My height is 1098â€™, Jasmine says â€˜My height is 112â€™ and Kim says â€˜Mine is 1.1â€™. What units were
Author(s): The Open University

## Activity 15

Suggest appropriate units for each of the following:

• (a) the age of the kitten when it is weaned;

• (b) the distance between one train station and the
Author(s): The Open University

## Activity 9

The diagram below shows an oatmeal cake marked into 12 equal portions. I want to give my sister a third of the cake. Where could I cut the cake, and what would be left over?

Author(s): The Open University

In the example below of a straightforward subtraction, in every column the digit at the top of the column is bigger than the digit at the bottom. Click on each step in turn to see how to carry out the calculation.

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