Algebra
A branch of mathematics in which symbols, usually letters of the alphabet are used to represent numbers.
A variable is a symbol that represents a number. It is denoted by letters such as x, a, b, v, y, or t. A variable can assume any of a set of values.
Example:
If a stands for the length of a square, then perimeter of the square is expressed as 4 × a; and the area of the square is expressed as a x a.
Example:
The temperature of a town is given by the chart below:
Day  Temperature t^{0} 
Tuesday  30^{0} 
Wednesday  25^{0} 
Thursday  31^{0} 
Friday  31^{0} 
It changes or varies but at one particular instant it has a fixed value. Hence it is represented by a variable t.
Directions: Identify the variable from the choices. Also write at least 10 examples of your own.
