Prime Factorization and Sieve of Eratosthenes

The video tutorial explains the concepts of prime and composite numbers, providing examples of each. It introduces the Sieve of Eratosthenes, a method to find prime numbers up to 100. The tutorial also covers how to find prime factors using two methods: the tree diagram and the division method, with examples for numbers 36 and 80. The video concludes with a call to action to like, share, and subscribe.

What is a prime number?

• A number that is even

• A number with exactly two factors

• A number with only one factor

• A number with more than two factors

Which of the following is a composite number?

• 2

• 5

• 3

• 4

What is the first step in the Sieve of Eratosthenes?

• Circle the number 2

• Cross out the number 1

• Cross out all even numbers

• Circle all prime numbers

Which number is circled after 2 in the Sieve of Eratosthenes?

• 4

• 3

• 5

• 6

What are prime factors?

• Factors that are even numbers

• Factors that are composite numbers

• Factors that are also prime numbers

• Factors that are odd numbers

In the tree diagram method, what do you do if a factor is composite?

• Write it as a product of two factors

• Circle it

• Multiply it by 2

• Ignore it

Using the division method, what is the first prime number used to divide 36?

• 7

• 3

• 2

• 5

What is the final product of prime factors for the number 36?

• 2 x 2 x 2 x 3

• 2 x 3 x 3 x 3

• 2 x 2 x 3 x 3

• 3 x 3 x 3 x 3

In the tree diagram method for 80, what are the factors of 10?

• 4 and 5

• 2 and 4

• 2 and 5

• 3 and 5

What is the final product of prime factors for the number 80?

• 2 x 2 x 2 x 2 x 5

• 2 x 2 x 3 x 5

• 2 x 3 x 3 x 5

• 2 x 2 x 2 x 3 x 5