How could you figure out if numbers are prime?

Answer 1

You could figure out a Prime number by the help of its factors. If it has only 2 factors which are 1 and number itself, then it is prime.

Answer 2

You can figure out the number is prime by dividing it by all numbers between that and 1. If it gets divided then it is not prime.

Answer 3

With difficulty.

You would need to check for divisibility by all integers up to (and including) the square root of the number.