How do I write a code to check if a number is prime using if-else statements?

Question

The basics of the code are good to go. I just don't understand how to express that the number has to be divisible by one and itself ONLY.

Answer 1

Just use the modulo operator %, and check all the numbers to at least the squar root of the number you want to check. You only have to check the odd numbers > 2. (Two is of course a prime number.)

Example:

10: 10 % 2 == 0 -> no prime
11: 11 % 2 != 0; 11 % 3 != 0; 4 no need to check; 5 ** 2 > 11 -> 11 prime! etc.

Answer 2

1.Input a number (as integer)

2.Use a for loop (ranging from 2 to the number) and check if the number is divided by them.

3.

If it is then print 'not prime'
If it's not print 'its prime'

[On the third step you can use if/else]

Answer 3

If loops would work, I'd appreciate a solution from that angle too. Thanks.

Answer 4

”Check all numbers” implicitly means using a loop, of course.

Start coding and try implement what we discussed above:

# Check if n is a prime.
for i in range(n + 1):
<Here comes your code>