What Is a Number Line? (Mathematics Lesson)
What Is a Number Line?A number line is a visual representation of the positive and negative numbers and zero.
Note: The number line goes on left and right forever.
Representing Numbers on a Number LineA number line allows all numbers to be represented.
Usually only integers are marked on a number line. The marks represent integers, such as -1 and 2 shown below:
Other numbers, that include fractions, can be represented in between the marks, such as -2.5 and 3/2 shown below:
Ordering of NumbersThe further right on the number line a number is, the greater it is. The further left on the number line a number is, the smaller it is:
This means that:
- any number is greater than any integer to its left.
- any number is less than any integer to its right.
- 3 is greater than 1.
- -1 is less than 1.
Using the Number LineA number line can be used to see how to add and subtract numbers.
Read more about how to use a number line to add and subtract.
ABSOLUTE NUMBERS AND THE NUMBER LINEThe absolute value, or modulus, of a number is the non-negative value of the number without regard to its sign.
The absolute value of a number is denoted by || either side of the number.
The absolute value of a positive number is just that number:
The absolute value of a negative number is the non-negative value of that number. It is that number with the minus sign ( - ) removed:
On a number line, the absolute value of a number is given by its distance from zero.
It can be seen that both 3 and -3 are 3 away from zero, and so both have an absolute value of 3: