# Challenge 2: Check for Prime Number

In this lesson, the user will check if a number is prime or not using recursion.

## We'll cover the following

# What is a prime number?

A **prime number** is a number greater than 1, that has only two divisors: 1 and the number itself. The first few prime numbers are:

$2, 3, 5, 7, 11, 13, 17, 19, 23, 29, .....$

**Composite** numbers are numbers that are not prime, that is, have divisors other than zero and itself

$4, 6, 8, 9, 10, 12, 14, 15, 16, 18.......$

The numbers $1$ and $0$ are neither prime nor composite.

All the numbers are either prime or composite, except for $0$ and $1$.

# Problem Statement

Write a recursive function, named `isPrime()`

that checks if a number is prime or not.

### Instructions

- The function should take two integers as input.
- The function should return boolean $-$ return $1$ if
*true*and the number is prime. Should return $0$ if*false*and the number is not prime. - The function should be recursive.

**Sample Input:** 7

**Sample Output:** 1

**Sample Input:** 9

**Sample Output:** 0

Good luck!

Note:Some test cases will pass by default and you need to pass all for the solution to be considered correct.

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