A
number line is a one-
dimensional graph in which the
integers are shown as specially-marked points evenly spaced on a line. It is often used as an aid in teaching simple
addition or
subtraction, especially involving negative numbers.
-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7
<----x----x----x----x----x----x----x----x----x----x----x----x----x----x----x-
--->
The number line is most often represented as being
horizontal (though it need not be so). It is divided into two symmetric halves by the
origin, i.e. the number
zero. Customarily,
positive numbers lie on the right side of zero, and negative numbers lie on the left side of zero (though it need not be so).
See also
Category:Elementary mathematics
fi:lukusuora
ja:数直線
zh:数线