Download Important Types of Numbers

Important Types of Numbers
FACTOR – A factor of a number will divide exactly into the number.
Example – The factors of 12 are 1, 2, 3, 4, 6 and 12
PRIME NUMBER – A number with exactly two factors.
Example – 11 is a prime number as its only factors are 1 and 11.
The first ten prime numbers are: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29
One is not a prime number as it only has one factor.
Two is the only even prime number
MULTIPLES – These are numbers with a common factor (alternatively they are numbers in the
appropriate ‘times table’).
Example – The multiples of 3 are: 3, 6, 9, 12, 15, 18, 21, 24 ……….
LOWEST COMMON MULTIPLE – The smallest value which is a multiple of both numbers.
Example – Find the lowest common multiple of 2 and 5
Multiples of 2: 2 4 6 8 10 12 14 16 18 20 22 ……
Multiples of 5: 5 10 15 20 ......
The lowest common multiple of 2 and 5 is 10
HIGHEST COMMON FACTOR – The largest number which is a factor of both numbers
Example – Find the highest common factor of 12 and 30
Factors of 12: 1, 2, 3, 4, 6, 12
Factors of 30: 1, 2, 3, 5, 6, 10, 15, 30
The highest common factor of 12 and 30 is 6.
SQUARE NUMBERS – These are numbers which are madeby multiplying a number by itself.
The first ten square numbers are: 1
4
1x1 2x2
9
3x3
Square numbers have an odd number of factors.
16
4x4
25 36
5x5 6x6
49
7x7
64
8x8
81
9x9
100
10x10