Massey logo
Home > College of Sciences > Institute of Fundamental Sciences >
Maths First > Algebra > Coordinate Systems and Graphs of Functions > Number Lines
MathsFirst logo College of Science Brandstrip
  Home  |  Study  |  Research  |  Extramural  |  Campuses  |  Colleges  |  About Massey  |  Library  |  Fees  |  Enrolment



Number Lines


We can visualise positive numbers as the distances to points on a line, measured to the right of some chosen "zero point" called the origin.


Negative numbers can then be thought of as corresponding to distances measured to the left of the origin:


We call this a number line.

For any number x, the number -x (called the negative of x) is the number which is the same distance from the origin as x, but on the opposite side. Note that this is also true when x itself is a negative number, for example -(-2) = 2.


Since the effect of placing a minus sign before a number is to "reflect" the number about the origin, it follows that for any number x (positive or negative):

-(-x) = x

That is, two successive "reflections" take you back to where you started.

| Graphs Index | 2D coordinates >>


   Contact Us | About Massey University | Sitemap | Disclaimer | Last updated: November 21, 2012     © Massey University 2003