1. Starter Questions Q1. Multiply out (a) a (6h – 3x)
Q2. 60p is spilt between William and Alan in a
ratio of 2:3. How much does each
person get?
Q3. Write down all the number that divide
into 12 without leaving a remainder.

2. To explain how to find Highest Common Factors
Using Factors
Learning Intention
To explain that a factor divides into a number without leaving a remainder
To explain how to find Highest Common Factors

3. Factors Example : Find the factors of 56.
Numbers that divide into 56 without leaving a remainder
F56 = 1 and 56
2 and 28
4 and 14
7 and

4. Factors Example : Find the factors of 64.
Numbers that divide into 64 without leaving a remainder
F64 = 1 and 64
2 and 32
4 and 16
8 and

5. Factors Example : Find the factors of 24.
Numbers that divide into 24 without leaving a remainder
F24 = 1 and 24
2 and 12
3 and 18
4 and

6. Factors Highest Common Factor Largest Same Number
We need to write out all factor pairs in order to find
the Highest Common Factor.

7. Factors Example : Find the HCF of 8 and 12. F8 = 1 and 8
Highest Common Factor
Example : Find the HCF of 8 and 12.
F8 = 1 and 8
2 and 4
F12 = 1 and 12
2 and 6
3 and 4
HCF = 4

8. Factors Example : Find the HCF of 6 and 18. F6 = 1 and 6
Highest Common Factor
Example : Find the HCF of 6 and 18.
F6 = 1 and 6
2 and 3
F18 = 1 and 18
2 and 9
3 and 6
HCF = 6

9. Factors Example : Find the HCF of 9 and 27. F9 = 1 and 9
Highest Common Factor
Example : Find the HCF of 9 and 27.
F9 = 1 and 9
3 and 3
F27 = 1 and 27
3 and 9
HCF = 9

10. Factors F ab =1 and ab F2b = 1 and 2b a and b 2 and b HCF = b
Highest Common Factor
Example : Find the HCF of ab and 2b.
F ab =1 and ab
a and b
F2b = 1 and 2b
2 and b
HCF = b

11. Factors Example : Find the HCF of 16 and 48. F16 = 1 and 16
Highest Common Factor
Example : Find the HCF of 16 and 48.
F16 = 1 and 16
2 and 8
4 and 4
F48 = 1 and 48
2 and 24
3 and 16
4 and 12
6 and 8
HCF = 6

12. Factors Example : Find the HCF of 4x and x2. F4x = 1, and 4x
Highest Common Factor
Example : Find the HCF of 4x and x2.
F4x = 1, and 4x
Fx2 = 1 and x2
2 and 2x
x and x
4 and x
HCF = x
Example : Find the HCF of 5 and 10x.
F5 = 1 and 5
F10x = 1, and 10x
2 and 5x
HCF = 5
5 and 2x
10 and x

13. Factors 8w 3y 4h ab Find the HCF for these terms (a) 16w and 24w
9y2 and 6y
(c) 4h and 12h2
(d) ab2 and a2b 3y 4h ab

14. Factors
Now try Ex 2
Ch15 (page 173)