### Number line

The **number line** (also called real line) is a geometric representation of the real numbers.

##### Explanation

It shows the whole numbers, negative numbers, rational numbers, irrational numbers, etc. For integers you get

Fractions are rational numbers, and are positioned on this line in between the integers

The square roots √0 = 0, √1, √4 = 2, √9 = 3 etc. are also on this line

The irrational numbers √2, √3 etc. also have their place

The number *e* is 2.7182… and the number π is 3.1415… and are of course on this line

Infinitely small (Δ*x*→0) has no fixed value and is therefore *not* locatable on the number line. There is no 'smallest number'. You won't find positive infinity (+ ∞) and negative infinity (− ∞) either, as these are no numbers.

## HistoryThe English mathematician John Wallis (1616 - 1703) is seen as the inventor of the number line. |