Question

Why is $0$ a real number?

Answer 1

$0$ is a real number:

Real numbers are numbers that include natural numbers, whole numbers, integers, irrational numbers, and rational numbers.

An integer is a set of whole numbers. Whole numbers above zero are said to be positive integers and whole numbers below zero are said to be negative integers.

$0$ is an integer, and we know all integers are real numbers

Hence, $0$ is a real number.