1. Types of Numbers Multiples and LCM Factors and HCF Prime numbers
Prime Decomposition
5-Apr-17
Created by Mr. Lafferty

2. Starter Questions www.mathsrevision.com Time Left : 5 7 8 4 6 1 3 2
mins
Starter Questions
31o
100o
92o
45o
5-Apr-17
Created by Mr. Lafferty

3. Types of Numbers www.mathsrevision.com Multiples Learning Intention
Success Criteria
We are learning that multiples are simply values in the times tables
We are learning how to find the Lowest Common Multiple.
Remember times tables and use them for multiples.
Apply sets of multiples to identify Lowest Common Multiples
5-Apr-17
Created by Mr. Lafferty

4. Types of Numbers www.mathsrevision.com Multiples
Example 1 : Find the first seven multiples of 3.
M3 = 3, 6 , 9, 12, 15, 18,21
Example 2 : Find the first five multiples of 4.
M4 = 4, 8 , 12, 16, 20, ………
5-Apr-17
Created by Mr. Lafferty

5. Types of Numbers www.mathsrevision.com Lowest Common Multiple Lowest
Smallest
Same
Number
We need to write out multiples in order to find
the Lowest Common Multiple.
5-Apr-17
Created by Mr. Lafferty

6. Types of Numbers www.mathsrevision.com Lowest Common Multiple
Example : Find the LCM of 3 and 4.
M3 = 3, 6 , 9, 12, 15, ………
M4 = 4, 8 , 12, 16, 20, ………
LCM = 12
5-Apr-17
Created by Mr. Lafferty

7. Now try Exercise 1 Ch5 (page 28) Types of Numbers
5-Apr-17
Created by Mr. Lafferty

8. Starter Questions www.mathsrevision.com 65o 52o 150o 5-Apr-17
Created by Mr. Lafferty

9. Types of Numbers www.mathsrevision.com Using Factors
Learning Intention
Success Criteria
We are learning that a factor divides into a number with no remainder
We are learning how to find Highest Common Factors
Identify factors using factor pairs
Find HCF for two numbers by comparing factors.
5-Apr-17
Created by Mr. Lafferty

10. Types of Numbers www.mathsrevision.com 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
5-Apr-17
Created by Mr. Lafferty

11. Types of Numbers www.mathsrevision.com Highest Common Factor Highest
Largest
Same
Number
We need to write out all factor pairs in order to find
the Highest Common Factor.
5-Apr-17
Created by Mr. Lafferty

12. Types of Numbers www.mathsrevision.com Factors
Example : Find the factors of 56.
Always divide by 1 and find its pair
F56 = 1 and 56
From 2 find other factors and their pairs
2 and 28
4 and 14
7 and
5-Apr-17
Created by Mr. Lafferty

13. Now try Exercise 2 Ch5 (page 30) Types of Numbers
5-Apr-17
Created by Mr. Lafferty

14. Starter Questions www.mathsrevision.com 4 cm 5 cm 5-Apr-17
Created by Mr. Lafferty

15. Types of Numbers www.mathsrevision.com Prime Numbers
Learning Intention
Success Criteria
We are learning what a prime number is.
understand the term Prime Number.
Find all prime between 1 and 200.
5-Apr-17
Created by Mr. Lafferty

16. Types of Numbers www.mathsrevision.com Prime Numbers
Definition : A prime number is a number with
exactly 2 factors.
Example : Is 7 a prime number. Explain?
Yes, only two factors 1,7
Example : Is 10 a prime number. Explain?
No, more than two factors 1,2,5,10
5-Apr-17
Created by Mr. Lafferty

17. Strike the two’s, strike the three’s the Sieve of Eratosthenes
when the multiples sublime, the numbers that remain are prime!
25 primes
Below 100
Slides 5 and 6 give the resource sheets.

18. Use the method of Eratosthenes to find all primes below 200
What is the largest prime <200?
46 primes below 200

19. 103 –
106 –
112
9000 –
110
107
7000 – 8000
117
114
119
120
3000 – 4000
127
2000 – 3000
135
1000 – 2000
168
0 – 1000
Number of Primes
Range ?

20. Worksheet – www.mathsrevision.com
Strike the two’s, strike the three’s the Sieve of Eratosthenes
Worksheet –
when the multiples sublime, the numbers that remain are prime!

21. Strike the two’s, strike the three’s the Sieve of Eratosthenes
Worksheet –
when the multiples sublime, the numbers that remain are prime!

22. Now try Exercise 3 Ch5 (page 32) Types of Numbers
5-Apr-17
Created by Mr. Lafferty

23. Starter Questions www.mathsrevision.com 119o 5 cm 8 cm 5-Apr-17
Created by Mr. Lafferty

24. Types of Numbers www.mathsrevision.com Prime Decomposition
Learning Intention
Success Criteria
We are learning what prime decomposition is.
Understand the term prime decomposition.
Decompose numbers to a product of prime only.
5-Apr-17
Created by Mr. Lafferty

25. Types of Numbers www.mathsrevision.com Prime Decomposition
A number is either Prime or Composite. (except for 0)
If it is composite, like 12, it can always be expressed as
a “product of primes”
Example : Express 12 as a “product of primes” 12
= 3 x 4
= 3 x 2 x 2 12 3 4 3 2
All Prime !
5-Apr-17
Created by Mr. Lafferty

26. Types of Numbers www.mathsrevision.com Prime Decomposition
Example : Express 18 as a “product of primes” 18
= 3 x 6
= 3 x 3 x 2 18 3 6 3 2 3
All Prime !
5-Apr-17
Created by Mr. Lafferty

27. Now try Exercise 4 Ch5 (page 35) Types of Numbers
5-Apr-17
Created by Mr. Lafferty