How to Test if a Number is Evenly Divisible by 9
Learn how to tell if a number is evenly divisible by nine.
Jason Marshall, PhD
To see if a number is evenly divisible by 9, add up the digits in the number and check if the resulting sum is evenly divisible by 9. If it is, then the original number is evenly divisible by 9 too. For example, is the number 3,240 evenly divisible by 9? Well, the sum of the digits in 3,240 is 3+2+4+0=9. Since 9 is evenly divisible by 9 (because 9/9 = 1), we know that 3,240 must be evenly divisible by 9 too.
For more, see How to Tell If a Number is Divisible by 7, 8, or 9
About the Author
Jason Marshall is the author of The Math Dude’s Quick and Dirty Guide to Algebra. He provides clear explanations of math terms and principles, and his simple tricks for solving basic algebra problems will have even the most math-phobic person looking forward to working out whatever math problem comes their way.