Understanding Factors and Prime Factors of 21

This video tutorial explains how to find the factors of 21 using a modified rainbow method. It demonstrates the use of divisibility rules to identify factors and highlights the prime factors of 21. The video also includes a trick to verify the number of factors and provides additional resources for further learning.

What method is introduced for finding factors of 21?

• Modified rainbow method

• Rainbow method

• Factor tree method

• Prime factorization

Which number is NOT a factor of 21?

• 1

• 3

• 5

• 7

Why is 21 divisible by 3?

• Because 21 is an even number

• Because the sum of its digits is divisible by 3

• Because it ends in 1

• Because it is a prime number

What is the purpose of a factor tree?

• To identify prime factors

• To divide numbers

• To find the sum of factors

• To multiply factors

What are the prime factors of 21?

• 5 and 4

• 3 and 7

• 2 and 11

• 1 and 21

How can you verify the total number of factors of 21?

• By adding the factors

• By multiplying the exponents of the prime factors plus one

• By dividing the largest factor by the smallest

• By counting only the prime factors

How many total factors does 21 have?

• 3

• 4

• 2

• 5

What is the significance of the number 1 in factorization?

• It is always a factor of any number

• It is a prime number

• It is only a factor of even numbers

• It is never a factor

What additional resource is suggested for learning more about factors?

• A math textbook

• A playlist

• A science journal

• A calculator