How to Know if a Number is Divisible by 9

A number is divisible by 9 if 9 multiplied by a whole number equals it.
••• Polka Dot Images/Polka Dot/Getty Images

Math is a part of everyday life, used for everything from music notation to construction work. In fact, math and numbers can be construed as the very key to unlocking the mystery of life itself. As such, everyone at some point needs to learn how to easily divide numbers. All you need is a basic understanding of simple addition. Here is an incredibly easy way to tell if any integer is divisible by 9, using the number 189 as an example.

    Use addition to add every single digit in your number together. (189 = 1 + 8 + 9 = 18)

    Add the numbers together again, if the sum is higher than 10. (18 = 1 + 8)

    Repeat steps 1 and 2 as many times as you need, until you get a single number. (9)

    Find out what that single number is. The original number is divisible evenly only if your end sum is nine. In this example, 189 would be divisible by 9 because the single number was 9.


    • The example used here (189) is merely that, an example. You can use this shortcut with any integer in existence.

Related Articles

How to Write an Improper Fraction As a Whole Number
How to Calculate 1/6th of Something
How to Write a Repeating Decimal As a Fraction
How to Turn Improper Fractions Into Whole Numbers
How to Round Numbers to Three Decimal Places
How to Round Decimals
How to Divide Rational Numbers
How to Take 24 Numbers & Calculate All Combinations
How to Round to the Nearest Ten Thousand
Definition of Successor and Predecessor in Math
How to Solve for Range
How to Do Exponents Outside of the Parenthesis
How to Add Fractions That Have Different Denominators
How to Do Math Problems in Your Head at Lightning Speed
How to Multiply Fractional Exponents
How to Round a Number to the Nearest Tenth
Three Methods of Estimating Math Problems
How to Solve an Arithmetic Sequence Problem With Variable...
What is the Identity Property of Multiplication?
How to Round to the Underlined Place Value Position