3. Learning Outcomes
Students able to
Find the multiples of any number
Find the common multiples of two or more numbers
Find the least common multiple (LCM)
Find the factors of any number
Find the common factors of two or more numbers
Find the Highest common factor(HCF)
Understand the definition of prime number and composite number
Know the divisibility of 2,3 and 5
4. Multiples
The numbers which are divisible by a number of then the numbers are
called the multiples of that number.
Multiples of 3=3,6,9,12,15,18…….
We can easily find these by the following process:
3=3*1=3
3*2=6
3*3=9
3*4=12
and so on
Multiples of 3
5. Common Multiples
Multiples of 3=3,6,9,12,15,18,21,24…….
Multiples of 4=4,8,12,16,20,24,28………
Numbers that are multiples of both 3 and 4 are called common
multiples of 3 and 4 .
So, Common multiples of 3 and 4 =12,24……..
6. Least Common Multiples (LCM)
The smallest common multiple is called least common multiples(LCM)
Common multiples of 3 and 4 =12,24……..
So, Least common multiples(LCM)= 12
7. Least Common Multiples (LCM)
One can find the LCM by this
following process-
4,6,9
Multiples of 4=4,8,12,16,20,24,28,32,36,40..
Multiples of 6=6,12,18,24,30,36,42..
Multiples of 9=9,18,27,36,45..
LCM:36
Find the LCM
of 4,6,9
2 4,6,9
3 2,3,9
2,1,3
LCM:2*3*2*3=36
8. Factors
The numbers that can divide a number evenly are called factors of
that number.
4=1,2,4
4 can be divided by 1,2 and 4
So, Factors of 4=1,2 and 4
We can find these factors easily by the
following process:
6= 1*6
= 2*3
Factors of 6=1,2,3,6
9. Common Factors
Factors of 8:
8= 1*8
= 2*4
Factors of 8=1,2,4,8
So, Common factors of 8 and 12=1,2,4
Factors of 12:
12=1*12
= 2*6
= 3*4
Factors of 12=1,2,3,4,6,12
10. The highest common factor of two numbers is
called highest common factor(HCF)
Common factors of 8 &12=1,2,4
So, Highest common factor(HCF)=4
Highest Common Factors (HCF)
11. Prime Numbers: The numbers which have only 1 and themselves
as their factors are called prime numbers.
Such as:2,3,5,7,11,13,17,19…….
Composite numbers: The numbers which can be made up by
multiplication of prime number.
4=2*2
12=2*2*3
20=2*2*5
4,12,20 are composite number
Prime numbers & Composite numbers
13. Divisibility of 2,3 and 5
Divisibility of 2
If these is a 0,2,4,6 or 8 (even number) in the ones place, the number is
divisible by 2
A. 2 2 4 B. 2 2 8 3
Divisible by 2 Not divisible by 2
Divisibility of 5
If these is a 0 or 5 in the ones place, those numbers are divisible by 5
A. 7 4 5 B. 3 5 3
Divisible by 5 Not divisible by 5
14. Divisibility of 2,3 and 5
If the sum of the digits of each place is a multiple of 3. So it is
divisible by 3.
A 261
2+6+1=9
9 is the multiple of 3
So, 261 is divisible by 3
B 263
2+6+3=11
9 is the not the multiple of 3
So, 263 is not divisible by 3
16. Group Work
Group A:
1. Find 3 multiples of 12
2. Find the factors of 14
Group B:
1. Find 3 multiples of 12
2. Find the factors of 15
Group C:
1. Find 3 multiples of 11
2. Find the factors of 16
17. Home Work
List 3 common multiples of 3 & 9
Find the LCM of 3 & 4
List the common factors of 9,15
Find the HCF of 8,12 &24
Write down the prime numbers between 1-25
