Divisibility Rule of 861

The divisibility rule for 861 is a method by which we can find out if a number is divisible by 861 or not without using the division method. Check whether 1722 is divisible by 861 using the divisibility rule.

Step 1: Multiply the last digit of the number by 2. Here in 1722, 2 is the last digit, so multiply it by 2. 2 × 2 = 4.

Step 2: Subtract the result from Step 1 with the remaining values but do not include the last digit. i.e., 172–4 = 168.

Step 3: As 168 is not a multiple of 861, the number is not divisible by 861. If the result from step 2 were a multiple of 861, then the number would be divisible by 861.

Learning the divisibility rule will help kids master division. Let’s learn a few tips and tricks for the divisibility rule of 861.

Know the multiples of 861:

Memorize the multiples of 861 (861, 1722, 2583, 3444, etc.) to quickly check the divisibility. If the result from the subtraction is a multiple of 861, then the number is divisible by 861.

Use the negative numbers:

If the result we get after the subtraction is negative, we will avoid the symbol and consider it as positive 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 861. For example, check if 3444 is divisible by 861 using the divisibility test. Multiply the last digit by 2, i.e., 4 × 2 = 8. Subtract 8 from the remaining digits excluding the last digit, 344–8 = 336. Since 336 is not a multiple of 861, 3444 is not divisible by 861.

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.

• Divisibility rule: A set of rules used to find out whether a number is divisible by another number without performing division.
   
• Multiples: The results we get after multiplying a number by an integer. For example, multiples of 861 are 861, 1722, 2583, etc.
   
• Subtraction: A process of finding the difference between two numbers by reducing one number from another.
   
• Integer: A number that includes all whole numbers, negative numbers, and zero.
   
• Verification: The process of confirming the accuracy of a result, often by using an alternative method such as division.