If a set is defined as containing all prime numbers less than 20, which of the f

If a set is defined as containing all prime numbers less than 20, which of the following numbers is NOT in the set?

If a set is defined as containing all prime numbers less than 20, which of the following numbers is NOT in the set?

Step 1: Understand what a prime number is. A prime number is a number greater than 1 that has no positive divisors other than 1 and itself.
Step 2: List all the prime numbers less than 20. The prime numbers are 2, 3, 5, 7, 11, 13, 17, and 19.
Step 3: Identify the number in question, which is 4.
Step 4: Check if 4 is a prime number. The number 4 can be divided by 1, 2, and 4, so it is not a prime number.
Step 5: Conclude that since 4 is not a prime number, it is not included in the set of prime numbers less than 20.

Prime Numbers – A prime number is a natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers.
Set Theory – Understanding the definition and properties of sets, particularly in relation to membership and elements.
Number Classification – Distinguishing between different types of numbers, such as prime numbers, composite numbers, and non-prime numbers.