A number line represents a series of integers extending to infinity in both directions – it is important that the numbers are evenly spaced and there are arrows on both ends. In real life we use negative numbers to represent debt (“in the red”), distance below sea (or ground) level and temperatures below zero degrees. But we haven’t always had a way to represent these concepts and at one time mathematicians didn’t believe negative numbers existed. (Read the about the history of negative numbers below).
- This video is not in Reverse (YouTube)
- This video is in Reverse (YouTube)
- History of Negative Numbers and a Brief History of Negative Numbers (nRich Maths)
- How to Add and Subtract Positive and Negative numbers (Maths is Fun)