1. FACTORS AND Greatest Common Factor

2. What are the factors of 12?,,,,, 12 126 43 What are the factors of 81?,,,, 13 81 9 27

3. Practice 1: Identify the numbers that are not factors of the numerals given in a set. 1. 12 {1,2,3,4,5,6,10,12} 2. 24 {1,2,3,4,6,8,9,12,15,19,24}

4. 3. 35 {1,5,7,9,15,27,30,35} 4. 42 {1,2,3,6,7,14,21,25,42} 5. 50 {1,2,3,4,5,10,25,30,50} 6. 18 {1,2,3,4,5,6,9,18} 7. 64 {1,2,3,4,5,6,8,18,32,64} 8. 15 {1,2,3,4,5,15}

5. Practice 2: Write the factors of the given numbers. 1. 202. 36 3. 48 4. 50 5. 80

6. Answer key: 1.20 = 1,2,4,5,10, 20 2.36 = 1,2,3,4,6,9,12,18,36 3.48 = 1,2,3,4,6,8,12,16,24,48 4.50 = 1,2,5,10,25,50 5.80 = 1,2,4,5,8,10,16,20,40,80

7. Practice 3: Write T if the statement is correct and F if the statement is wrong. 1.4 is the factor of 21 2.1,3, and 4 are the only factors of 12.

8. 3. 9 is not a factor of 99 4. 1,2,4, and 8 are the factors of 8 5. 3 is a factor of 26 6. 1 is a factor of all numbers

9. What are the factors of 12?,,,,, 12 126 43 1 2 40 420 What are the factors of 40 ? 8 10 5

10. Therefore, the common factors of 12 and 40 are… 1, 2, and 4 But the Greatest Common Factor is …. 4

11. What are the factors of 6?,,, 1 6 32 13 What are the factors of 15 ?,,, 15 5 What are the factors of 9? 193

12. Therefore, the common factors of 6, 9 and 15 are… 1 and 3 But the Greatest Common Factor is …. 3

13. Practice 1: List all the factors of each number in ascending order. Then find the common factors and Greatest Common Factor.

14. 1.6 = 8 = CF = GCF =

15. Answer: 1.6 = 1, 2, 3, 6 8 = 1, 2, 4, 8 CF = 1, 2 GCF = 2

16. 2. 9 = 18 = CF = GCF =

17. Answer: 2. 9 = 1, 3, 9 18 = 1, 2, 3, 6, 9,18 CF = 1, 3, 9 GCF = 9

18. 3. 12 = 15 = CF = GCF =

19. Answer: 3. 12 = 1, 2, 3, 4, 6, 12 15 = 1, 3, 5, 15 CF = 1, 3 GCF = 3

20. 4. 8 = 12 = CF = GCF =

21. Answer: 4. 8 = 1, 2, 4, 8 12 = 1, 2, 3, 4, 6, 12 CF = 1, 2, 4 GCF = 4

22. 5. 9 = 18 = 27 = CF = GCF =

23. Answer: 5. 9 = 1, 3, 9 18 = 1, 2, 3, 6, 9, 18 27 = 1, 3, 9, 27 CF = 1, 3, 9 GCF = 9

24. Practice 2: Find the CF and GCF 1.12 =2. 27 = 18 =36 = CF= CF = GCF =GCF =

25. 3. 15 =4. 42 = 21 =28 = CF =CF = GCF =

26. 5. 25 = 30 = 40 = CF = GCF =

27. Answers: Find the CF and GCF 1.12 = 1, 2, 3, 4, 6, 12 18 = 1, 2, 3, 6, 9, 18 CF =1, 2, 3, 6 GCF =6

28. 2. 27 = 1, 3, 9, 27 36 = 1, 2, 3, 4, 6, 9, 12, 18, 36 CF= 1, 3, 9 GCF =9

29. 3. 15 =1, 3, 5, 15 21 = 1, 3, 7, 21 CF =1, 3 GCF =3

30. 4. 42 = 1, 2, 3, 6, 7, 14, 21, 42 28 = 1, 2, 4, 7, 14, 28 CF =1, 2, 7, 14 GCF =14

31. 5. 25 = 1, 5, 25 30 = 1, 2, 3, 5, 6, 10, 30 40 = 1, 2, 4, 5, 8, 10, 20, 40 CF = 1, 5 GCF = 5

32. Assignment: Answer the ff. ___1. What is the sum of all the factors of 18? ___2. What is the sum of all the common factors of 24 and 16?

33. ___3. What is the GCF of two consecutive numbers? ___4. What is the GCF of two consecutive even numbers? ___5. What is the biggest number that can exactly divide 12, 24, and 18?

34. __6. The GCF of two numbers is 6. The second number is three times the first number. What are the two numbers?

35. T