# Any tips?

hi guys.
i’m a little stuck, any tips?

Prime Number Finder: Prime Number Finder | Codecademy

The challenge isn’t placing any maximum value restriction on `n`.

Here are a few things to consider:

• Suppose the argument to the function is `6`, then the expected result should be `[2, 3, 5]` whereas your function will return `[2, 3, 5, 7]`. This contradicts the challenge specification “… and returns all the prime numbers from `1` to `n` (inclusive)”. Your function doesn’t work properly when the provided argument is in the range 1 to 6 as your function is returning extra prime numbers.

• You are deciding whether a number is prime or not by checking its divisibility by the numbers `2`, `3`, `5` and `7`. That approach will work when the provided argument is about `100`. But for numbers greater than `100`, you can’t just rely on divisibility by `2`, `3`, `5` and `7`.
For Example, if the argument to the function is `121`, then `121` is included in your list of `primes`. But `121` is most certainly not a prime number (`11 x 11 = 121`) because the factors of `121` are `1, 11, 121`. You could tack on

``````and num % 11 != 0
``````

to your if condition. But, what happens if the provided argument is `169`? Your function would identify `169` as a prime number even though it is not (since `13 x 13 = 169`).
You can’t write an if condition with a finite number of possibilities beforehand which exhaustively guarantees that your function will work for all `n`.

Your if condition will work up to a certain point and then it won’t. Manually tacking on more operands after the `and` is not going to solve the underlying issue. You need to re-think your approach.

that’s a really interesting perspective , but how to fix it?