207 LearnersLast updated on May 26th, 2025
Divisibility Rule of 391
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 391.
What is the Divisibility Rule of 391?
The divisibility rule for 391 is a method by which we can find out if a number is divisible by 391 or not without using the division method. Check whether 782 is divisible by 391 with the divisibility rule.
Step 1: Since 391 does not have a simple divisibility rule like smaller numbers, we will need to rely on the known properties or factors of 391. Note that 391 = 17 × 23.
Step 2: Check if the number is divisible by both 17 and 23. If 782 is divisible by both, then it is divisible by 391.
Step 3: For 17, divide 782 by 17. 782 ÷ 17 = 46, which is an integer, so 782 is divisible by 17. Now check for 23. 782 ÷ 23 = 34, which is also an integer, so 782 is divisible by 23.
Step 4: Since 782 is divisible by both 17 and 23, it is also divisible by 391.
Tips and Tricks for Divisibility Rule of 391
Learning divisibility rules will help you master division. Let’s learn a few tips and tricks for the divisibility rule of 391.
- Know the factors of 391: Memorize the factors of 391 (17 and 23) to quickly check the divisibility. If a number is divisible by both factors, it is divisible by 391.
- Use the factor method: Break down the number into its prime factors and check divisibility with each factor.
- Repeat the process for large numbers: For larger numbers, verify divisibility by both 17 and 23 using the factor method described.
- Use the division method to verify: You can use the division method to verify and crosscheck results. This will help verify and also learn.
- Practice with examples: Regular practice with examples will help avoid common mistakes.
Common Mistakes and How to Avoid Them in Divisibility Rule of 391
The divisibility rule for 391 helps us quickly check if a given number is divisible by 391, 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 divisibility by both factors.
Ensure you divide the number by both 17 and 23 to confirm divisibility by 391.
Mistake 2
Incorrect division calculations.
Double-check your division calculations to avoid errors.
Mistake 3
Stopping the process after one check.
Make sure to check divisibility by both factors, not just one.
Mistake 4
Confusing the factors of 391.
Remember that 391 = 17 × 23, and keep this in mind when checking for divisibility.
Mistake 5
Forgetting to practice regularly.
Regular practice will help reinforce the steps and prevent confusion.
Divisibility Rule of 391 Examples
Problem 1
Is 782 divisible by 391?
Yes, 782 is divisible by 391.
Explanation
To determine if 782 is divisible by 391:
1) Split 782 into two parts: 78 and 2.
2) Add these two parts together: 78 + 2 = 80.
3) Divide the sum by 391 to check divisibility: \( 782 \div 391 = 2 \).
4) Since the result is a whole number, 782 is divisible by 391.
Problem 2
Check the divisibility rule of 391 for 1173.
No, 1173 is not divisible by 391.
Explanation
To check the divisibility of 1173 by 391:
1) Split 1173 into two parts: 117 and 3.
2) Add these two parts together: 117 + 3 = 120.
3) Divide the sum by 391 to check divisibility: ( 1173 div 391 approx 3.00 ).
4) Since the result is not a whole number, 1173 is not divisible by 391.
Problem 3
Is -1564 divisible by 391?
Yes, -1564 is divisible by 391.
Explanation
To check if -1564 is divisible by 391:
1) Consider the absolute value, 1564.
2) Split 1564 into two parts: 156 and 4.
3) Add these two parts together: 156 + 4 = 160.
4) Divide the sum by 391 to check divisibility: ( 1564 div 391 = 4 ).
5) Since the result is a whole number, -1564 is divisible by 391.
Problem 4
Can 2349 be divisible by 391 following the divisibility rule?
No, 2349 isn't divisible by 391.
Explanation
To check if 2349 is divisible by 391:
1) Split 2349 into two parts: 234 and 9.
2) Add these two parts together: 234 + 9 = 243.
3) Divide the sum by 391 to check divisibility: ( 2349 div 391 approx 6.01 ).
4) Since the result is not a whole number, 2349 is not divisible by 391.
Problem 5
Check the divisibility rule of 391 for 7820.
Yes, 7820 is divisible by 391.
Explanation
To check the divisibility of 7820 by 391:
1) Split 7820 into two parts: 782 and 0.
2) Add these two parts together: 782 + 0 = 782.
3) Divide the sum by 391 to check divisibility: ( 7820 div 391 = 20 ).
4) Since the result is a whole number, 7820 is divisible by 391.
FAQs on Divisibility Rule of 391
1.What is the divisibility rule for 391?
2.How many numbers are there between 1 and 1000 that are divisible by 391?
3.Is 1564 divisible by 391?
4.What if I get a remainder after division?
5.Does the divisibility rule of 391 apply to all integers?
6.How can children in India use numbers in everyday life to understand Divisibility Rule of 391?
7.What are some fun ways kids in India can practice Divisibility Rule of 391 with numbers?
8.What role do numbers and Divisibility Rule of 391 play in helping children in India develop problem-solving skills?
9.How can families in India create number-rich environments to improve Divisibility Rule of 391 skills?
Important Glossaries for Divisibility Rule of 391
- Divisibility Rule: The set of rules used to determine whether a number is divisible by another number.
- Factors: Numbers that divide another number completely without leaving a remainder. For 391, these are 17 and 23.
- Prime Numbers: Numbers greater than 1 that have no divisors other than 1 and themselves. 17 and 23 are prime numbers.
- Integer: A whole number that can be positive, negative, or zero.
- Remainder: The number left over after division when a number does not divide another number exactly.
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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.
Fun Fact
: She loves to read number jokes and games.
