Lets look at the meaning of the terms discrete and continuous. We call a variable to be discrete when it takes number in the form of integers or fractions. This indicates that the variable input is countable in nature. When a variable takes any value present between two discrete numbers then it is considered a continuous variable. Example, a spoonful of sugar is a discrete variable whereas a flask full of water is a continuous variable. The amount of sugar in a spoon is countable whereas the amount of water in flask is not. The gradations present on the flask are a discrete approximate measure of the amount of water present in it.