Understanding Prime and Composite Numbers

The video tutorial explains the concepts of prime and composite numbers using arrays. It introduces arrays as arrangements of objects in rows and columns and uses tile examples to illustrate the difference between prime and composite numbers. Prime numbers have exactly two factors, one and the number itself, while composite numbers have more than two factors. The video also discusses why the number one is neither prime nor composite. Mnemonic devices and songs are used to help remember these concepts. Practical examples are provided to identify prime numbers, and the Sieve of Eratosthenes is introduced as a method to find prime numbers.

What is an array in the context of arranging numbers?

• A random collection of numbers

• A single line of numbers

• An arrangement of objects in rows and columns

• A list of numbers in a sequence

Which of the following is a characteristic of a prime number?

• It can be divided by any number

• It has more than two factors

• It is always an even number

• It has exactly two different factors

Which number is a prime number?

• 12

• 15

• 31

• 21

What defines a composite number?

• It has exactly two factors

• It has more than two different factors

• It is always an odd number

• It cannot be divided by any number

Which of the following is a composite number?

• 7

• 31

• 12

• 29

Why is the number one neither prime nor composite?

• It is a multiple of two

• It has only one factor

• It is an even number

• It has more than two factors

What mnemonic device can help remember prime numbers?

• Prime numbers are lonely

• Prime numbers are always even

• Prime numbers love company

• Prime numbers are picky people

Which number is not a prime number?

• 17

• 2

• 29

• 51

What is the Sieve of Eratosthenes used for?

• To arrange numbers in an array

• To find composite numbers

• To eliminate prime numbers

• To identify prime numbers

Which list contains only prime numbers?

• 1, 2, 3, 5, 7

• 2, 3, 5, 7, 11

• 4, 6, 8, 10

• 9, 15, 21, 25