Divisibility Rule of 9


 
 
Concept Explanation
 

Divisibility Rule of 9

Divisibility Rule of 9:

A number is divisible by 9, if the sum of its digits is divisible by 9.

Justification:

Let us first consider case of a two digit number:

 n=overline{ab} be a two digit number. Then, n can be written as

         n = 10a + b, where b is units digit of n.

Rightarrow    n = 9a + a + b

Rightarrow    n = a multiple of 9 + ( a + b )

Rightarrow    n is a multiple of 9, if ( a + b ) is a multiple of 9

Thus, a two digit number is divisible by 9, if the sum of its digits is divisible by 9.

.... (More Text Available, Login?)
Sample Questions
(More Questions for each concept available in Login)
Question : 1

if the three digit numbers 6 y 8 is divisible by 9 then the value of y is

Right Option : D
View Explanation
Explanation
Question : 2

Replace by a  digit so that the number is divisible by 9.

1______ 80498

Right Option : B
View Explanation
Explanation
Question : 3

Which of the following number is divisible by 9 ?

642,999,888,772

Right Option : A
View Explanation
Explanation
 
 
Related Videos
Language - English


Students / Parents Reviews [10]