You have seen different types.of numbers in the earlier classes
Eg Natural numbers, whole numbers, integers etc
When you want to divide a.pizza into 8 equal parts, each person get 1/8 of it. So we need numbers in fractional form.
A number that can be written in the form of p/q where p and q are integers and q shoul.not be equal to zero .( since division with zero is not defined yet)