Divisibility Rule of 809

The divisibility rule for 809 is a method by which we can determine if a number is divisible by 809 without using the division method. Check whether 1618 is divisible by 809 with the divisibility rule.

Step 1: Double the last digit of the number, here in 1618, 8 is the last digit, so double it. 8 × 2 = 16

Step 2: Subtract the result from Step 1 from the remaining values, excluding the last digit. That is, 161 – 16 = 145.

Step 3: As 145 is not a multiple of 809, the number is not divisible by 809. If the result from step 2 is a multiple of 809, then the number is divisible by 809.

Learning the divisibility rule will help kids master division. Let’s learn a few tips and tricks for the divisibility rule of 809.

Know the multiples of 809:  

Memorize the multiples of 809 (809, 1618, 2427, 3236…etc.) to quickly check the divisibility. If the result from the subtraction is a multiple of 809, then the number is divisible by 809.

Use the negative numbers:  

If the result we get after the subtraction is negative, we will consider the absolute value for checking the divisibility of a number.

Repeat the process for large numbers:  

Students should keep repeating the divisibility process until they reach a small number that is divisible by 809.  
For example: Check if 4845 is divisible by 809 using the divisibility test.  
Double the last digit, i.e., 5 × 2 = 10  
Subtract 10 from the remaining digits excluding the last digit, 484 – 10 = 474  
Still, 474 is not a multiple of 809, so 4845 is not divisible by 809.

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 learn.

• Divisibility rule: A set of rules used to find out whether a number is divisible by another number without performing actual division.

• Multiples: Multiples are the results obtained after multiplying a number by an integer. For example, multiples of 809 are 809, 1618, 2427, 3236, etc.

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

• Subtraction: Subtraction is the process of finding the difference between two numbers by reducing one number from another.

• Absolute Value: The non-negative value of a number without regard to its sign. For example, the absolute value of -16 is 16.