Identifying Prime and Composite Numbers Under 100

This video tutorial explains the concepts of prime and composite numbers, providing examples and methods to identify them. It uses a hundred chart to visually demonstrate how to find prime numbers under 100 and discusses the unique nature of the number 1. The video concludes with a practice session for viewers to apply their understanding.

What defines a prime number?

• A number with exactly three factors

• Any even number greater than 2

• A number with exactly two factors: 1 and itself

• A number that can be divided by numbers other than 1 and itself

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CCSS.4.OA.B.4

Which of the following is a composite number?

• 3

• 21

• 2

• 11

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CCSS.4.OA.B.4

Why is 2 considered a prime number?

• It is the only even number that has exactly two factors: 1 and itself

• It has more than two factors

• It can be divided by numbers other than 1 and itself

• It cannot be divided by 2

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CCSS.4.OA.B.4

How can even numbers be classified on the hundred chart?

• All even numbers are prime

• All even numbers except 2 are composite

• All even numbers are neither prime nor composite

• Only numbers ending in 0 are composite

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CCSS.4.OA.B.4

What happens to multiples of 3 in the process of identifying prime numbers?

• They are ignored in the process

• They are all considered prime

• They are marked as composite if they have more than two factors

• Only multiples of 3 that are odd are considered

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CCSS.4.OA.B.4

Which number is the next prime number after 5?

• 8

• 9

• 7

• 6

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CCSS.4.OA.B.4

How many prime numbers are there under 100?

• 30

• 23

• 25

• 28

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CCSS.4.OA.B.4

What is the status of the number 1?

• Neither prime nor composite

• Composite

• Prime

• Both prime and composite

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CCSS.4.OA.B.4

Which of the following numbers is composite?

• 19

• 14

• 17

• 31

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CCSS.4.OA.B.4

What characteristic do prime numbers have?

• They are all even numbers

• They have exactly two factors: 1 and itself

• They have exactly three factors

• They can be divided evenly by numbers other than 1 and itself

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CCSS.4.OA.B.4