A prime number is a number that is divisible only by 1 and itself. For example, 13 is prime since only 1 and 13 divide evenly
into 13; 14 however is not prime since 1, 2, 7, and 14 divide evenly into it.

In this lesson, we'll write a function called `prime`

to test if a number is prime. The function will return `true`

if the
number if prime, and `false`

if the number is not prime. To keep things simple, we'll implement something related to the
"naive" test described on Wikipedia (link).

We'll use these conditions to test for primality of a number, held in variable $n$:

- Know that $2$ is prime (and the only even prime number).
- If $n$ is even, then two will divide evenly into it, and we'll conclude that the number is not prime.
- We'll only test if odd numbers divide evenly into $n$, since even numbers will only divide evenly into $n$ is $n$ is also even, and we have the first bullet point already.
- We'll only test numbers from 3 up to $\sqrt{n}$ since if $n$ has other factors, one must be $< \sqrt{n}$.

`if`

statement and the `for`

statement.
Type your code here:

See your results here:

This code will not run. In the

`prime`

function, you need to fix the following:
- What will you fill into the first
`if`

statement to see if $2$ divides evenly into $n$, causing the function to return`false`

? - What will you fill into the
`for`

statement, to start at $3$ and count up to $\sqrt{n}$, going next to 5, then 7, then 9, etc. (i.e. only odd numbers)? Dismiss.

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