Prime Number – An integer whose only factors are 1 and itself

2, 3, 5, 7,11, 13, 17, 19

Prime Factor Tree for 60

Write 60 at the top of the page 60

60 = prime number 2 x 30 2

2

30

15

3 5

30 = prime number 2 x 15

15 = prime number 3 x prime number 5

60 is all the prime numbers 2 x 2 x 3 x 5 multiplied together

Draw factor trees for:

24 and 60

FACTOR TREES

24 60

4 6 4 15

2 2 2 3 2 2 3 5

24 = 2 x 2 x 2 x 3 60 = 2 x 2 x 3 x 5

24 = 2 x 2 x 2 x 3

60 = 2 x 2 x 3 x 5

HCF = 2 x 2 x 3 = 12

Find the HCF for 16 and 30

FACTOR TREES

16 30

4 4 2 15

2 2 2 2 3 5

16 = 2 x 2 x 2 x 2 30 = 2 x 3 x 5

16 = 2 x 2 x 2 x 2

30 = 2 x 3 x 5

HCF = 2

1. 30 and 45

2. 45 and 20

3. 40 and 80

4. 36 and 24

5. 32 and 16

HCF = 15

HCF = 5

HCF = 40

HCF = 11

HCF = 16

Complete the

minute glass activity

Complete

Minute Glass Activity

Lowest Common Multiple LCM

Multiple of 5 5, 10, 15, 20, 25, 30 ....Multiple of 88, 16, 24, 32, 40, 48 .....Multiple of 4242, 84, 126, 168, 210 ...

The LCM of two or more numbers is the smallest

number that is a multiple of each of the numbers.

24, 48, 72, 96, 120, 144,….

60, 120, 180, 240, 300,....

Find the lowest common multiple of 4 and 18

4, 8, 12, 16, 20, 24, 28, 32, 36, 40…….

18, 36, 54, 72…….

LCM = 36

Find the Lowest Common Multiple

1. 15 and 6

2. 9 and 12

3. 24 and 6

4. 4 and 18

5. 15 and 16

LCM = 30

LCM = 36

LCM = 24

LCM = 36

LCM = 240

Complete the minute glass activity

Complete

Minute Glass Activity

2460

Venn Diagram24 = 2 x 2 x 2 x 3

60 = 2 x 2 x 3 x 5

22

3

2 5

HCF = 2 x 2 x 3 = 12

LCM = 2 x 2 x 2 x 3 x 5 = 120

HCF is the region of

intersection2 x 2 x 3 = 12

LCM is all the numbers in the circles

multiplied together 2 x 2 x 2 x 3 x 5=120

Find the HCF and LCM of the following:

1. 6 and 15

2. 20 and 30

3. 14 and 42

4. 24, 30 and 54Answers:

1.HCF = 3, LCM = 30

2.HCF = 10, LCM = 60

3.HCF = 14, LCM = 42

4.HCF = 6, LCM = 1080