119 LearnersLast updated on May 26th, 2025
Divisibility Rule of 77
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 77.
What is the Divisibility Rule of 77?
The divisibility rule for 77 involves checking a number for divisibility by both 7 and 11, as 77 is the product of these two numbers. To determine if a number is divisible by 77, you must confirm it is divisible by both 7 and 11 using their respective rules.
Example: Check whether 847 is divisible by 77.
Step 1: Apply the divisibility rule of 7.
Multiply the last digit by 2. For 847, the last digit is 7: 7 × 2 = 14.
Subtract the result from the rest of the number: 84 - 14 = 70.
Since 70 is a multiple of 7, 847 is divisible by 7.
Step 2: Apply the divisibility rule of 11.
Alternate sum: For 847, calculate (8 + 7) - 4 = 15 - 4 = 11.
Since 11 is divisible by 11, 847 is divisible by 11.
Step 3: Since 847 is divisible by both 7 and 11, it is divisible by 77.
Tips and Tricks for Divisibility Rule of 77
Learn divisibility rules to help master division. Here are a few tips and tricks specific to the divisibility rule of 77.
Know the multiples of 7 and 11:
Memorize the multiples of 7 (7, 14, 21, 28...) and 11 (11, 22, 33, 44...) to check divisibility quickly.
Use negative numbers:
If the result of subtraction is negative, consider it as positive for checking divisibility.
Repeat the process for large numbers:
Keep repeating the divisibility process until you reach a number easily checked for divisibility by 7 and 11.
Use the division method to verify:
Use the division method to verify and cross-check your results. This will help in learning and confirming accuracy.
Common Mistakes and How to Avoid Them in Divisibility Rule of 77
The divisibility rule of 77 helps quickly check if a number is divisible by both 7 and 11. Here are some common mistakes and solutions.
Mistake 1
Not checking for both 7 and 11.
Always verify that a number is divisible by both 7 and 11.
Mistake 2
Including the last digit in subtraction for the rule of 7.
Exclude the last digit when subtracting and include all remaining digits.
Mistake 3
Not repeating the process when the result is large.
Continue the process until you get a small number divisible by 7 and 11.
Mistake 4
Not considering negative values.
Treat negative values as positive when checking for divisibility.
Mistake 5
Confusing the steps.
Practice regularly to avoid confusion and ensure accuracy.
Divisibility Rule of 77 Examples
Problem 1
A cargo ship is transporting 6,160 crates. Is the total number of crates divisible by 77?
Yes, 6,160 is divisible by 77.
Explanation
To determine if 6,160 is divisible by 77, use the divisibility rule:
1) Split the number into two parts: 61 and 60.
2) Check if both parts are divisible by 7 and 11.
61 is not divisible by 7, but it is divisible by 11 (11 x 5.545).
60 is divisible by neither 7 nor 11.
3) Since neither part is divisible by both 7 and 11, 6,160 is not divisible by 77.
Problem 2
A library has 924 books, and they want to organize them into equal groups in 77 shelves. Can they do this?
Yes, 924 is divisible by 77.
Explanation
To verify if 924 can be evenly distributed:
1) Divide 924 by 77.
2) 924 ÷ 77 = 12.
3) As the division results in a whole number, 924 is divisible by 77.
Problem 3
A conference has 1,540 attendees. They want to create teams of 77 attendees each. Is it possible?
Yes, 1,540 is divisible by 77.
Explanation
Explanation: To check if 1,540 is divisible by 77:
1) Divide 1,540 by 77.
2) 1,540 ÷ 77 = 20.
3) Since the division yields an integer, 1,540 is divisible by 77.
Problem 4
A factory produces 2,123 gadgets in a month. Can these gadgets be packed in boxes containing 77 gadgets each?
No, 2,123 is not divisible by 77.
Explanation
To determine divisibility:
1) Divide 2,123 by 77.
2) 2,123 ÷ 77 ≈ 27.571.
3) The division does not result in a whole number, so 2,123 is not divisible by 77.
Problem 5
A researcher finds 3,388 specimens of a plant species. Can they divide them into groups of 77 for analysis?
Yes, 3,388 is divisible by 77.
Explanation
To confirm divisibility:
1) Divide 3,388 by 77.
2) 3,388 ÷ 77 = 44.
3) The result is a whole number, indicating that 3,388 is divisible by 77.
FAQs on Divisibility Rule of 77
1.What is the divisibility rule for 77?
2.How many numbers are there between 1 and 100 that are divisible by 77?
3. Is 154 divisible by 77?
4.What if I get 0 after subtraction?
5.Does the divisibility rule of 77 apply to all integers?
6.How can children in India use numbers in everyday life to understand Divisibility Rule of 77?
7.What are some fun ways kids in India can practice Divisibility Rule of 77 with numbers?
8.What role do numbers and Divisibility Rule of 77 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 77 skills?
Important Glossaries for Divisibility Rule of 77
- Divisibility Rule: The set of rules used to determine if a number is divisible by another number without actual division.
- Multiples: Results obtained by multiplying a number by an integer. For example, multiples of 7 and 11.
- Integers: The set of whole numbers, including negative numbers and zero.
- Subtraction: The process of finding the difference between two numbers.
- Alternate Sum: A method used in the rule for 11, involving the sum and difference of alternating digits.
Explore More numbers
About BrightChamps in India
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.
