Logic Building/Phase 2 - Level 2: Number-based Looping Logic/Program

Check if Number is Prime

Check if a number is prime.

Logic BuildingIntermediate

Logic Building

# Take number
num = int(input("Enter a number: "))

# Check prime
if num < 2:
    print("Not prime")
else:
    is_prime = True
    for i in range(2, int(num ** 0.5) + 1):
        if num % i == 0:
            is_prime = False
            break
    
    if is_prime:
        print("Prime")
    else:
        print("Not prime")

Output

Enter a number: 17
Prime

Enter a number: 15
Not prime

Check if number has any divisors.

Key Concepts:

Numbers < 2 are not prime
Check divisors from 2 to sqrt(num)
If any divisor found, not prime

Print Primes Between 1-100

Fibonacci Series Up to N