POC01234 SCU Online Proof of Concept

Subtracting and dividing fractions

Let‘s say you drive to SCU each day.

SCU is 16 km from your home.

You are low on fuel and have to stop to buy petrol on the way.

The petrol station is 8 km from your home.

What fraction of your trip to SCU do you still have to drive after buying petrol?

You have travelled 8 km of a 16 km trip. You still have \(16-8=8\) km to go.

You have travelled \(\frac{8}{16}\) of your trip to Uni. You still have \(\frac{8}{16}\) of your trip to go.

 

You have probably noticed that \(\frac{8}{16}=\frac{1}{2}\)

The petrol station is at the half-way point of your drive to Uni.

After you buy petrol you still have half your trip to go.

Subtracting fractions

When subtracting fractions with the same denominator (in this case ‘16’), we subtract one numerator from the other, and the denominator stays the same.

\[\frac{16}{16}-\frac{8}{16}=\frac{16-8}{16}=\frac{8}{16}\]

Dividing fractions

When dividing fractions by a whole number, we divide the numerator of the fraction by the whole number. The denominator stays the same.

\[\frac{16}{16}\div2=\frac{16\div2}{16}=\frac{8}{16}\]

Once we have the result we may be able to simplify the fraction. In this case \(\frac{8}{16}=\frac{1}{2}\)