Is It A Prime Number, Yes or No?

1. Is It A Prime Number, Yes or No? Jonathan Brinkerhoff

2. There are different kinds of numbers. You know about whole numbers, like 5, and fractions like ⅓. You know about odd and even numbers. Today, we’ll learn about another kind of number – prime numbers.

3. I’m going to show you some numbers. Some are prime and some are not. When you think you know what makes a number prime or not, raise your hand.

4. 3 is a prime number 3 = 1 X 3

5. 4 is not a prime number 4 = 1 X 4 4 = 2 X 2

6. 5 is a prime number 5 = 1 X 5

7. 6 is not a prime number 6 = 1 X 6 6 = 2 X 3

8. 7 is a prime number 7 = 1 X 7

9. 12 is not a prime number 12 = 1 X 12 12 = 2 X 6 12 = 3 X 4

10. 13 is a prime number 13 = 1 X 13

11. 15 is not a prime number 15 = 1 X 15 15 = 3 X 5

12. What do you think a prime number is?

13. Congratulations! You figured out that a prime number has only two factors, itself and 1.

14. Let’s Practice! If it’s not a prime number If it’s a prime number

15. 8

16. 9

17. 14

18. 17

19. 21

20. 10

21. 19

22. Well done! You can correctly identify prime numbers.

24. 2 is a prime number 2 = 1 X 2

25. 9 is not a prime number 9 = 1 X 9 9 = 3 X 3

26. 11 is a prime number 11 = 1 X 11

27. 14 is not a prime number 14 = 1 X 14 14 = 2 X 7

28. What do you think a prime number is?