Exploring Prime Numbers and the Sieve of Eratosthenes

This video tutorial introduces prime numbers, explaining their unique properties and why the number one is not considered prime. It demonstrates the Sieve of Eratosthenes, an ancient method for identifying prime numbers, and guides viewers through applying this technique to find primes up to 50. The tutorial encourages learners to practice the method on their own up to 100, reinforcing their understanding of prime numbers and preparing them for prime factorization.

What is a prime number?

• A number with more than two factors.

• A number with exactly two factors.

• A number with only one factor.

• A number that is divisible by 2.

Which of the following is NOT a prime number?

• 4

• 2

• 3

• 5

What ancient method is used to find prime numbers?

• Sieve of Eratosthenes

• Pythagorean Theorem

• Fibonacci Sequence

• Euclidean Algorithm

What is the first step in the Sieve of Eratosthenes?

• Cross out all even numbers.

• Mark the number 1 as not prime.

• Circle all prime numbers.

• Cross out all multiples of 3.

Which number is the only even prime number?

• 4

• 2

• 3

• 1

After marking 2 as prime, what should you do next?

• Mark 5 as prime.

• Cross out all multiples of 3.

• Mark 3 as prime.

• Cross out all multiples of 2.

What is the next prime number after 5 in the Sieve of Eratosthenes?

• 9

• 7

• 6

• 8

Which multiples should be crossed out after marking 7 as prime?

• 7, 14, 21, 28

• 14, 21, 28, 35

• 21, 28, 35, 42

• 28, 35, 42, 49

What should you do after crossing out multiples of 11?

• Mark 13 as prime.

• Cross out multiples of 13.

• Mark 17 as prime.

• Cross out multiples of 17.

What is the final step after completing the Sieve of Eratosthenes up to 100?

• Review the prime numbers.

• Mark all remaining numbers as prime.

• Cross out all remaining numbers.

• Save the sheet for future reference.