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Last updated on February 12th, 2025

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Divisibility Rule of 3

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Foundation
Intermediate
Advance Topics

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 3.

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What is the Divisibility Rule of 3?

The divisibility rule for 3 is a method by which we can find out if a number is divisible by 3 or not without using the division method. Check whether 123 is divisible by 3 with the divisibility rule.  


Step 1: Add up all the digits of the number. In 123, the digits are 1, 2, and 3, so add them: 1 + 2 + 3 = 6.  


Step 2: Check if the result from Step 1 is a multiple of 3. Since 6 is a multiple of 3, 123 is divisible by 3. If the sum is not a multiple of 3, then the number isn't divisible by 3.
divisibility rule of 3

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Tips and Tricks for Divisibility Rule of 3

Learn divisibility rules to help kids master division. Let’s learn a few tips and tricks for the divisibility rule of 3.

 
Know the multiples of 3:

Memorize the multiples of 3 (3, 6, 9, 12, 15, etc.) to quickly check the divisibility. If the sum of the digits is a multiple of 3, then the number is divisible by 3.  


Repeat the process for large numbers:

Students should keep repeating the divisibility process until they reach a small number that is easily recognized as a multiple of 3. For example, check if 1947 is divisible by 3 using the divisibility test. Add the digits: 1 + 9 + 4 + 7 = 21. Since 21 is a multiple of 3, 1947 is divisible by 3.


Use the division method to verify:

Students can use the division method as a way to verify and cross-check 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 3

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Divisibility Rule of 3 Examples

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Problem 1

Can the total number of fruits in a basket, 123, be divided evenly into three groups?

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Explanation

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Problem 2

Check if the number 456 can be split evenly among three friends.

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Explanation

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Problem 3

Is the total number of books, 789, divisible by 3?

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Explanation

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Problem 4

Determine if the number 101 can be evenly divided by 3.

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Explanation

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Problem 5

Is the total score of a game, 372, divisible by 3?

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Explanation

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FAQs on Divisibility Rule of 3

1.What is the divisibility rule for 3?

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2.How many numbers are there between 1 and 100 that are divisible by 3?

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3.Is 45 divisible by 3?

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4.What if I get 0 after adding the digits?

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5.Does the divisibility rule of 3 apply to all integers?

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Important Glossaries for Divisibility Rule of 3

  • Divisibility rule: The set of rules used to find out whether a number is divisible by another number or not. For example, a number is divisible by 3 if the sum of its digits is a multiple of 3.

 

  • Multiples: Multiples are the results we get after multiplying a number by an integer. For example, multiples of 3 are 3, 6, 9, 12, etc.

 

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

 

  • Sum: The result of adding numbers together. For the divisibility rule of 3, it involves adding all the digits of a number.

 

  • Verify: To confirm the accuracy through another method, such as using division to check the result obtained from the divisibility rule.
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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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