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Find a simple fraction of a quantity where the result is a whole number, with and without digital technologies (ACMNA127)

Source: Australian Curriculum, Assessment and Reporting Authority (ACARA)

Some important vocabulary for fractions

3 rows of 6 yellow stars.In mathematics the word 'of ' has a special meaning.

If we have 3 rows of 6 stars we can draw a picture to represent this.

We write 3 × 6 = 18.

We can use 'of ' with fractions too.

18 oranges arranges in 2 rows of 9. 12 of the oranges are circled.

When we are asked, for example, to find \(\dfrac{2}{3}\) of 18 oranges, we take it to mean that we divide the 18 oranges into three equal parts and then take two of these parts.

This gives \(\dfrac{2}{3}\) of 18 = 12.

Note that the result is the same as \(\dfrac{2}{3} × \dfrac{18}{1} = \dfrac{2 × 18}{3 × 1} = \dfrac{36}{3} = 12\).

When 'of ' is used with fractions it means multiplication.