Divisibility Rule of 18

The divisibility rule for 18 is a method by which we can find out if a number is divisible by 18 or not without using the division method. A number is divisible by 18 if it is divisible by both 2 and 9.

Check whether 234 is divisible by 18 with the divisibility rule.

Step 1: Check divisibility by 2. A number is divisible by 2 if its last digit is even. In 234, 4 is the last digit, which is even, so 234 is divisible by 2.

Step 2: Check divisibility by 9. A number is divisible by 9 if the sum of its digits is a multiple of 9. Add the digits of 234: 2 + 3 + 4 = 9. Since 9 is a multiple of 9, 234 is divisible by 9.

Step 3: Since 234 is divisible by both 2 and 9, it is divisible by 18.

Learning the divisibility rule will help kids to master division. Let’s learn a few tips and tricks for the divisibility rule of 18.

• Know the multiples of 18: Memorize the multiples of 18 (18, 36, 54, 72, 90, etc.) to quickly check divisibility. If the result from the checks is a multiple of 18, then the number is divisible by 18.

• Use the sum of digits: If checking for 9, always remember to sum the digits and see if they form a multiple of 9.

• Repeat the process for large numbers: Students should keep repeating the divisibility process for both 2 and 9 until they reach a definitive conclusion.

• Use the division method to verify: Students can use the division method as a way to verify and crosscheck their results. This will help them to verify and also learn.

• Divisibility rule: The set of rules used to find out whether a number is divisible by another number or not.

• Multiples: The results we get after multiplying a number by an integer. For example, multiples of 18 are 18, 36, 54, etc.

• Integers: Numbers that include all whole numbers, negative numbers, and zero.

• Sum of digits: The total obtained by adding all the digits of a number.

• Even number: A number that is divisible by 2.