Divisibility Rule of 85

The divisibility rule for 85 helps us determine if a number is divisible by 85 without performing division. Check whether 2890 is divisible by 85 with the divisibility rule.

Step 1: Check if the number is divisible by both 5 and 17. For 2890, since the last digit is 0, it is divisible by 5.

Step 2: Add the digits of the number to see if the sum is divisible by 17. 2 + 8 + 9 + 0 = 19, which is not divisible by 17.

Since 2890 is divisible by 5 but not by 17, it is not divisible by 85.

Learning the divisibility rule will help kids master division. Let’s learn a few tips and tricks for the divisibility rule of 85.

• Know the multiples of 85: Memorize the multiples of 85 (85, 170, 255, 340, ... etc.) to quickly check divisibility. If both conditions (divisibility by 5 and 17) are met, the number is divisible by 85.
   
• Use the sum of the digits for 17: To check divisibility by 17, the sum of the digits of the number should be checked. If it is a multiple of 17, the number is divisible by 17.
   
• Repeat the process for large numbers: Students should keep repeating the divisibility process for large numbers to ensure accuracy.
  
  For example: Check if 3400 is divisible by 85 using the divisibility test. The last digit is 0, so it is divisible by 5. Adding the digits, 3 + 4 + 0 + 0 = 7, which is not divisible by 17. Thus, 3400 is not divisible by 85.
   
• Use the division method to verify: Students can use the division method to verify and crosscheck their results. This will help them to verify and also learn.

• Divisibility rule: The set of rules used to determine whether a number is divisible by another number or not. For example, a number is divisible by 5 if its last digit is 0 or 5.
   
• Multiples: Multiples are results obtained by multiplying a number by an integer. For example, multiples of 85 are 85, 170, 255, 340, etc.
   
• Integers: Integers are numbers that include all whole numbers, negative numbers, and zero.
   
• Sum of digits: The process of adding all the digits of a number together.
   
• Verification: The process of using division to confirm the result of a divisibility test.