PROPERTIES OF FACTORS
1) 1 and the number itself is always the factor of the number.
2) 1 is the smallest factor and the number is the highest factor.
3) A number can have more than 2 factors.
4) A factor of the number is less than or equal to the given number.
5) The factors of any numbers are finite.

How to find common factors of pair of numbers.

1) Find factors of each of the numbers.
2) Select the commons factors from each number.



Example 1Find common factors of 20 and 30 .
Solution Find factors of each of the numbers.
Factor of 20 are = 1,20,2,10,4,5
Factors of 30 are = 1,30,2,15,3,10,5,6
Common factors are = 1,2, 5

Example 2 Find common factors of 36 and 45 .
Solution Find the factors of each of the numbers.
Factors of 36 are = 1,36,2,18,3,12,4,9,6 .
Factors of 45 are = 1,45,3,15,5,9 .
Common factors are = 1,3,9
Exercise
1) Find the common factors of following numbers pair of numbers.
a) 32,68


b) 50,75


c) 31, 53


d) 81,114


e) 17,51


f) 81, 102


g) 21,42


h) 230, 130


i) 27,57


j) 52, 80