Introduction to Math Variables

Students are often introduced to variables in pre-algebra or sometimes in earlier math classes. Non-numerical symbols represent variables in mathematical expressions and equations.

Variables and Constants

Mathmeticians use numbers, symbols and operators to construct mathematical statements. Numbers are constants, and variables are most often represented by letters of the alphabet.

Variables Notation

Variables are usually written as letters near the end of the English alphabet (x, y, z). You can also use Greek letters.

Variables as Unknowns

A variable in an expression represents an unknown quantity. The numerical value of a variable depends on the other variables, constants and operators in an equation or inequality.

Variables Can Change

The numerical value of a variable is not fixed. Unlike constants, which are unchanging (1 always equals 1), variables can change (x might equal 1 in one situation, but it might equal 4 in another).

Solving Single Variable Equations

You solve a simple equation in one unknown by adding, subtracting, multiplying or dividing both sides of the equation by the same thing to isolate the variable by itself on one side of the equals sign. For example, to find the value of x in the equation 3x = 12, divide both sides by 3 [e.g. 3x/3 = 12/3] to get x = 4.

References

• Math Speak Blog on Variables