This video lesson is designed for 6-12-year-old children. In this lesson, we will learn how to find prime factors of a number.

First, let us understand what are prime numbers, factors, and prime factorization.

What is a Prime Number?

Prime numbers are natural numbers that have only two factors, one and the number itself. For example, 2, 3, 5, 7, 11, 13, etc.

What is a Factor?

A factor is a number that divides a given number without leaving any remainder. For example, factors of 12 are 2, 2, and 3.

Finding Factors of the Following Numbers:

• 36 = 2×2 × 3×3
• 24 =2x2x2 × 3
• 60 = 2×2 × 3 × 5
• 18 = 2 × 3×3
• 72 = 2x2x2 × 3×3
• 45 = 3×3 × 5
• 40 = 2x2x2 × 5
• 50 = 2 × 5×5
• 48 = 2x2x2x2 × 3
• 30 = 2 × 3 × 5
• 42 = 2 × 3 × 7

What is Prime Factorization?

Prime Factorization is a process of finding which prime numbers multiply together to make the original number. It is a way of expressing a number as a product of its prime factors.

For example, the prime factors of 15 are 3 and 5 (where 3 and 5 are prime factors)

Let us take another example and find prime factors of number 147?

To find prime factors of 147. Let’s start dividing 147 by the first prime number i.e. 2

• Can 147 be divided by 2?
No, it can’t because the unit digit is not 2, 4, 6, 8 or 0.
• Let’s try the next prime number, 3:
Yes, we can divide 147 by 3
• 147 ÷ 3 = 49
Now, let us find the prime factor of 49 to break it further.
• Can 49 be divided by 5?
No, because the unit digit of 49 doesn’t end with 5 or 0.
• Can we divide 49 by 7?
Yes, 49 ÷ 7 = 7. Here, the remainder is 7, which is a prime number.

Thus, the factors of 147 are 3x7x7 and the prime factors of 147 are 3 and 7.

As shown in the video, help the child find prime factors of a few numbers.

Benefits of Finding Prime Factor

Prime numbers can only be divided by 1 or themselves, so they cannot be factored any further. They are the basic building blocks of all numbers. It also helps in cryptography (Cryptography is a method of protecting information and communicating through codes. Prime factorization plays a vital role in creating a unique code using these numbers).Watch the video to learn more about the prime factors and how to find prime factors of a number.

For more math lessons, visit: https://theglobalmontessorinetwork.org/math-resources/
Video created by Justine McNeilly (Metro East Montessori, Granite City, IL)

Elementary | Math | Prime Factors (English) |

Tags

• Elementary
• English
• Math