1. Factor Trees

2. What are Factor Trees for? Ever seen a question that said find the prime factors of a number? Use factor trees to work it out! Contents

3. How to find the prime factors of a number with factor trees Click Next to find out! Contents

4. How to make a factor tree First Choose a number Find two numbers that when multiplied together equal the number First Choose a number Find two numbers that when multiplied together equal the number Contents 8 4 2 Stop when a branch gets to a prime number, as you can see 4 X 2 equals 8, 2 is a prime number so we stop that branch but 4 isn’t. 2 2 The prime factors of 8 are 2, 2 and 2 So 2 X 2 X 2 = 8 The prime factors of 8 are 2, 2 and 2 So 2 X 2 X 2 = 8 OK

5. How to make a factor tree First Choose a number Find two numbers that when multiplied together equal the number First Choose a number Find two numbers that when multiplied together equal the number Contents 8 4 2 Stop when a branch gets to a prime number, as you can see 4 X 2 equals 8, 2 is a prime number so we stop that branch but 4 isn’t. 2 2 The prime factors of 8 are 2, 2 and 2 So 2 X 2 X 2 = 8 The prime factors of 8 are 2, 2 and 2 So 2 X 2 X 2 = 8 OK Skip

6. What are the prime factors of 81? 81 Contents 9 9 3 3 3 3 Type the factors separated by spaces: HELP!

7. What are the prime factors of 81? 81 Contents 9 9 3 3 3 3 Type the factors separated by spaces: HELP! Correct!

8. Work this out 20 Contents Type the factors from largest to smallest separated by spaces: HELP! Click below to open paint to work out:

9. Well Done! Contents You can also write the prime factors in indexed notation: 5 X 2 2

10. Contents What are Factor Trees for? How to find the prime factors of a number with factor trees How to make a factor tree What are the prime factors of 81? Work this out Resume