divisibility rule for 9

Rule:
A number is divisible by 9,if the sum of its digits is divisible by 9.
Example 1:
Is 567891 divisible by 9?
Solution:
The sum of digits in the number 567891 is 36.
36 is divisible by 9 since 36/9=4.
According to the rule given above,the number 567891is divisible by 9.
Example 2:
Is 782342 divisible by 9?
Solution:
The sum of digits in the number 782342 is 26.
26 is not divisible by 9 since 26/9 leaves 8 as remainder.
As per the rule given above,the number 782342 is not divisible by 9.