Understanding Prime and Composite Numbers

The video introduces prime numbers, defining them as positive integers greater than one with only two factors: one and itself. It distinguishes between prime and composite numbers, noting that any multiple of a prime, other than the prime itself, is composite. The video highlights unique properties of primes, such as 2 being the only even prime and 2 and 5 being the only primes ending in those digits. It further explores the possible ending digits of primes, noting that primes can end in 1, 3, 7, or 9, except for 2 and 5. The video concludes by emphasizing the infinite nature of primes ending in certain digits.

What is a prime number?

• A number that ends in zero

• A number that is a multiple of another number

• A positive integer greater than one with only two factors

• A number with more than two factors

Which of the following is a composite number?

• 3

• 2

• 4

• 5

Which number is the only even prime?

• 3

• 5

• 2

• 7

Which of these numbers can a prime number end with?

• 9

• 6

• 4

• 0

How many prime numbers end in 5?

• Infinite

• Two

• One

• None

Which digits can prime numbers end with, excluding 2 and 5?

• 3, 5, 7

• 2, 5, 8

• 0, 2, 4, 6

• 1, 3, 7, 9