A variable is like a placeholder or a box that can hold different values. In math, it's often represented by a letter, like x or y. The value of a variable can change depending on the situation. For example, if you have the equation y = 2x + 3, the value of y depends on the value of x. So, if you change x, the value of y will change too i.e., if x = 2, then y = 2(2) + 3 = 7.

Some more examples of variables in real life are:

Consider x is the changing price of apple due to season change. If you buy 3 apples, each costing x dollars, you pay 3x. Here x is a variable.

Consider Celsius to Fahrenheit conversion formula - F = (9/5)​C + 32. In this formula, C is the temperature in Celsius, and F is the temperature in Fahrenheit. If C=0, then F = (9/5)(0) + 32 = 32 degrees Fahrenheit. Here C and F are variables. Types of Variables Variables can be classified into different types based on their characteristics including independent variables, dependent variables, discrete variables and continuous variables each serving distinct purposes in mathematical world.

Listed below are different types of variables:

1. Independent Variables: These are variables that can be freely chosen or manipulated. They represent inputs or factors that influence the outcome of a mathematical relationship or function. Eg: The time spent studying (in hours) before an exam. This variable can be freely chosen or manipulated by the student.

2. Dependent Variables: Dependent variables are determined by the values of other variables in a mathematical equation or system. They represent the outputs or results of a mathematical relationship or function. Eg: The score obtained on the exam. This variable is determined by the amount of time spent studying and represents the outcome of the study effort.