If you add up the digits, and the sum is divisible by 9 or a multiple of 9.
* * * * *
For really big numbers you may need to find the digital root (sum of digits) of the digital root.
The divisibility rule for 9 is that the sum of the digits of a number must add up to 9 or a multiple of 9.
For example, is 81 divisible by 9? Lets find out! 8+1=9. Then it is divisible by 9.
Chat with our AI personalities
If the number is divisible by 3 then its divisible by 9. If you forgot what the divisble rule for three this is how, add up all the numbers then whatever the sum is and if the sum can go into three then its divisible by 3 and 9.
It is even and the sum of its digits is divisible by 9.
Its digits add up to 9 so therefore it is divisible by 9
By tautology. If it did not work, it would not be a divisibility rule!
What is the divisblity rule by 8
There is no easy rule for divisibility by 34.