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Last updated on February 12th, 2025

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Divisibility Rule of 18

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The divisibility rule is a way to find out whether a number is divisible by another number without using the division method. In real life, we can use the divisibility rule for quick math, dividing things evenly, and sorting things. In this topic, we will learn about the divisibility rule of 18.

Divisibility Rule of 18 for Vietnamese Students
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What is the 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.

 

divisibility rule of 18

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Tips and Tricks for Divisibility Rule of 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.
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Common Mistakes and How to Avoid Them in Divisibility Rule of 18

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Divisibility Rule of 18 Examples

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Problem 1

Is 324 divisible by 18?

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Explanation

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Problem 2

Check the divisibility rule of 18 for 612.

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Explanation

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Problem 3

Is 275 divisible by 18?

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Explanation

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Problem 4

Can 972 be divisible by 18 following the divisibility rule?

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Explanation

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Problem 5

Check the divisibility rule of 18 for 450.

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Explanation

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FAQs on Divisibility Rule of 18

1. What is the divisibility rule for 18?

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2.How many numbers are there between 1 and 100 that are divisible by 18?

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3.Is 54 divisible by 18?

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4.What if I get 0 after summing the digits for 9?

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5.Does the divisibility rule of 18 apply to all integers?

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6.How can children in Vietnam use numbers in everyday life to understand Divisibility Rule of 18?

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7.What are some fun ways kids in Vietnam can practice Divisibility Rule of 18 with numbers?

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8.What role do numbers and Divisibility Rule of 18 play in helping children in Vietnam develop problem-solving skills?

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9.How can families in Vietnam create number-rich environments to improve Divisibility Rule of 18 skills?

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Important Glossaries for Divisibility Rule of 18

  • 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.
Professor Greenline from BrightChamps

About BrightChamps in Vietnam

At BrightChamps, we know numbers mean much more than digits—they unlock endless opportunities! Our aim is to help children across Vietnam strengthen key math skills, focusing today on the Divisibility Rule of 18 and especially on the Divisibility Rule—taught in a way that’s lively, fun, and easy to understand. Whether your child is measuring the speed of a roller coaster at Suoi Tien Theme Park, keeping track of scores at local football matches, or managing their allowance to buy the latest gadgets, mastering numbers boosts their confidence for everyday challenges. Our lessons are interactive and enjoyable. Since kids in Vietnam learn differently, we adapt our methods to fit every learner’s style. From the vibrant streets of Ho Chi Minh City to the scenic views of Ha Long Bay, BrightChamps makes math come alive, making it exciting all across Vietnam. Let’s make the Divisibility Rule a fun part of every child’s math journey!
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Hiralee Lalitkumar Makwana

About the Author

Hiralee Lalitkumar Makwana has almost two years of teaching experience. She is a number ninja as she loves numbers. Her interest in numbers can be seen in the way she cracks math puzzles and hidden patterns.

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Fun Fact

: She loves to read number jokes and games.

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