What is a variable? Distinguish between a discrete and continuous variables

A characteristic or a phenomenon which is capable of being measured and changes its value overtime is called a variable.

The differences between a discrete and continuous variables are :

Discrete Variable
A discrete variable can take only certain values.Its value changes only by finite ‘jumps’. It jumps from one values to another but does not take any intermediate value between them.
For example, in number of students in class Xlth could be 1,2,4,10,11,15,20, etc.

Continuous Variable :

A continuous variable is the one which can take any value in a specified interval.
For exomp/e, temperature recorded of patients a hospital, wages of all workers in a factory, etc.