Question

Name all the sets that -4.2 belongs to

Answer 1

Not a natural number.
Not an integer.
Not a whole number.
Yes, a rational number!
Yes, a real number!

Answer 2

what is a set??

Answer 3

A set is a collection of items. These could be numbers, people, functions, colors, et al. It is simply a collection. So, each of @ParthKohli 's sets have a specific definition, I recommend looking them up.

Answer 4

Likewise,
— natural numbers are the set of numbers like 1,2,3,4,5,6,7,8..........
— whole numbers are the set of numbers like 0,1,2,3,4,5,6,7,8......(note that this is just the set of natural numbers with a zero included).
— integers are the set of whole numbers with negative numbers like .....-3,-2,-1 included.
— rational numbers are the set of numbers that can be expressed as a quotient of two integers.
— real numbers are the set of numbers that exist in nature, even if they are not rational(or irrational).