This notebook was prepared by [Thunder Shiviah](https://github.com/ThunderShiviah). Source and license info is on [GitHub](https://github.com/ThunderShiviah/code_guild).
Primes are numbers which are only divisible by 1 and themselves.
5 is a prime since it can only be divided by itself and 1. 9 is not a prime since it can be divided by 3 (3*3 = 9). 1 is not a prime for reasons that only mathematicians care about.
To check if a number is prime, we can implement a basic algorithm, namely: check if a given number can be divided by any numbers smaller than the given number (note: you really only need to test numbers up to the square root of a given number, but it doesn't really matter for this assignment).
In :def list_primes(n): primes =  for p in range(2, n + 1): # we add a '+ 1' to be inclusive. for num in range(2, p): if p % num == 0: break else: primes.append(p) return primes
In :%run -i test_list_primes.py
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