Basic science: understanding numbers

3.5 Negative numbers

Active content not displayed. This content requires JavaScript to be enabled, and a recent version of Flash Player to be installed.

Intuitively you might consider zero as the lowest possible number, there can’t be anything less than nothing, right? Numbers below zero seem unnatural, or complicated to understand.

The video uses temperature to illustrate that negative numbers are not uncommon and are used all the time. Negative numbers are written with a minus symbol in front of them. For example, a normal household freezer is often set to -18 ˚C (or 18 degrees below zero).

Activity 3.2 Temperatures and negative numbers

Allow about 15 minutes

There is a wide range of temperatures that might be experienced by visiting different countries. The temperatures of the five countries in the video were all different, with two below 0 ˚C. Post your response to these questions in the forum thread for this activity and discuss with your fellow students:

  • How hot or cold does it get where you live?
  • Where are the hottest and coldest places you’ve visited?
  • Can you think of any other everyday situations where you use negative numbers?