
    Given a student's performance threshold score n, determine the number of prime number exercises that should be included in their personalized math practice set by calculating how many prime numbers exist below n. This calculation will help dynamically adjust the difficulty level of the student's customized learning path based on their current mathematical proficiency.
    

    
def count_Primes_nums(n):
    """
    Given a student's performance threshold score n, determine the number of prime number exercises that should be included in their personalized math practice set by calculating how many prime numbers exist below n. This calculation will help dynamically adjust the difficulty level of the student's customized learning path based on their current mathematical proficiency.
    

    """
def count_Primes_nums(n):
    """
    Given a student's performance threshold score n, determine the number of prime number exercises that should be included in their personalized math practice set by calculating how many prime numbers exist below n. This calculation will help dynamically adjust the difficulty level of the student's customized learning path based on their current mathematical proficiency.
    

    """
    ctr = 0
    for num in range(n):
        if num <= 1:
            continue
        for i in range(2, num):
            if num % i == 0:
                break
        else:
            ctr += 1
    return ctr