186 LearnersLast updated on May 26th, 2025
Divisibility Rule of 105
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 105.
What is the Divisibility Rule of 105?
The divisibility rule for 105 is a method by which we can find out if a number is divisible by 105 or not without using the division method. A number is divisible by 105 if it is divisible by 3, 5, and 7 (since 105 = 3 × 5 × 7).
Check whether 315 is divisible by 105 using the divisibility rule.
Step 1: Check divisibility by 3. The sum of the digits is 3 + 1 + 5 = 9, which is divisible by 3.
Step 2: Check divisibility by 5. The last digit is 5, which means it is divisible by 5.
Step 3: Check divisibility by 7. Double the last digit and subtract it from the rest of the number: 31 - (5 × 2) = 21, which is a multiple of 7.
Since 315 is divisible by 3, 5, and 7, it is divisible by 105.
Tips and Tricks for Divisibility Rule of 105
Learning the divisibility rules will help kids master division. Let’s learn a few tips and tricks for the divisibility rule of 105.
- Know the multiples of 105: Memorize the multiples of 105 (105, 210, 315, 420, etc.) to quickly check divisibility. If a number meets all divisibility rules for 3, 5, and 7, it is divisible by 105.
- Use the divisibility rules for 3, 5, and 7: Ensure you are familiar with each rule separately to apply them effectively for 105.
- Repeat the process for large numbers: Students should keep repeating the divisibility process for each component (3, 5, and 7) until they confirm divisibility by all three.
- 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 verify and also learn.
Common Mistakes and How to Avoid Them in Divisibility Rule of 105
The divisibility rule of 105 helps us quickly check if a given number is divisible by 105, but common mistakes like calculation errors can lead to incorrect results. Here, we will understand some common mistakes and how to avoid them.
Mistake 1
Not checking all divisibility rules.
Students should ensure they check divisibility by 3, 5, and 7 separately.
Divisibility Rule of 105 Examples
Problem 1
A shipment contains 525 boxes. Is the total number of boxes divisible by 105?
Yes, 525 is divisible by 105.
Explanation
To check the divisibility of 525 by 105, we need to confirm divisibility by 3, 5, and 7.
1) Check divisibility by 3: Sum of digits is 5 + 2 + 5 = 12, which is divisible by 3.
2) Check divisibility by 5: The last digit is 5, so it is divisible by 5.
3) Check divisibility by 7: Multiply the last digit by 2, 5 × 2 = 10. Subtract from the rest, 52 – 10 = 42, which is divisible by 7.
Since 525 is divisible by 3, 5, and 7, it is divisible by 105.
Problem 2
A farmer has 630 apples and wants to pack them equally into boxes that can hold a number of apples divisible by 105. Can he do this?
Yes, 630 apples can be packed equally into boxes divisible by 105.
Explanation
For 630 to be divisible by 105, it must be divisible by 3, 5, and 7.
1) Divisibility by 3: Sum of digits is 6 + 3 + 0 = 9, which is divisible by 3.
2) Divisibility by 5: The last digit is 0, so it is divisible by 5.
3) Divisibility by 7: Multiply the last digit by 2, 0 × 2 = 0. Subtract from the rest, 63 – 0 = 63, which is divisible by 7.
Since 630 is divisible by these three numbers, it is divisible by 105.
Problem 3
A concert hall has 840 seats. Are the seats arranged in rows that are divisible by 105?
Yes, 840 seats can be arranged in rows divisible by 105.
Explanation
To check if 840 is divisible by 105, confirm divisibility by 3, 5, and 7.
1) Divisibility by 3: Sum of digits is 8 + 4 + 0 = 12, which is divisible by 3.
2) Divisibility by 5: The last digit is 0, so it is divisible by 5.
3) Divisibility by 7: Multiply the last digit by 2, 0 × 2 = 0. Subtract from the rest, 84 – 0 = 84, which is divisible by 7.
Thus, 840 is divisible by 105.
Problem 4
A company manufactures 945 widgets each week. Is this weekly production divisible by 105?
Yes, 945 is divisible by 105.
Explanation
For 945 to be divisible by 105, it must be divisible by 3, 5, and 7.
1) Divisibility by 3: Sum of digits is 9 + 4 + 5 = 18, which is divisible by 3.
2) Divisibility by 5: The last digit is 5, so it is divisible by 5.
3) Divisibility by 7: Multiply the last digit by 2, 5 × 2 = 10. Subtract from the rest, 94 – 10 = 84, which is divisible by 7.
Therefore, 945 is divisible by 105.
Problem 5
There are 1,155 chairs to be set up in a conference hall. Can the chairs be arranged in sections divisible by 105?
Yes, 1,155 can be arranged in sections divisible by 105.
Explanation
To determine if 1,155 is divisible by 105, we check divisibility by 3, 5, and 7.
1) Divisibility by 3: Sum of digits is 1 + 1 + 5 + 5 = 12, which is divisible by 3.
2) Divisibility by 5: The last digit is 5, so it is divisible by 5.
3) Divisibility by 7: Multiply the last digit by 2, 5 × 2 = 10. Subtract from the rest, 115 – 10 = 105, which is divisible by 7.
Thus, 1,155 is divisible by 105.
FAQs on Divisibility Rule of 105
1.What is the divisibility rule for 105?
2.How many numbers are there between 1 and 1000 that are divisible by 105?
3.Is 420 divisible by 105?
4.What if I meet only two of the divisibility rules?
5.Does the divisibility rule of 105 apply to all integers?
6.How can children in Thailand use numbers in everyday life to understand Divisibility Rule of 105?
7.What are some fun ways kids in Thailand can practice Divisibility Rule of 105 with numbers?
8.What role do numbers and Divisibility Rule of 105 play in helping children in Thailand develop problem-solving skills?
9.How can families in Thailand create number-rich environments to improve Divisibility Rule of 105 skills?
Important Glossaries for Divisibility Rule of 105
- Divisibility rule: A set of rules used to determine if a number is divisible by another number without performing division.
- Multiple: A product obtained by multiplying a number by an integer. For example, multiples of 105 are 105, 210, 315, etc.
- Integer: A whole number that can be positive, negative, or zero.
- Subtraction: The process of finding the difference between numbers by removing one from another.
- Verification: The process of confirming the accuracy of a result, often by different means such as division.
Explore More numbers
Previous to Divisibility Rule of 105
About BrightChamps in Thailand
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.
Fun Fact
: She loves to read number jokes and games.
