Divisibility Rule of 43

The divisibility rule for 43 is a method by which we can find out if a number is divisible by 43 or not without using the division method. Check whether 602 is divisible by 43 with the divisibility rule.
 

Step 1: Multiply the last digit of the number by 9, here in 602, 2 is the last digit. Multiply it by 9. 2 × 9 = 18.
 

Step 2: Subtract the result from Step 1 from the remaining values but do not include the last digit. i.e., 60 - 18 = 42.
 

Step 3: As 42 is not a multiple of 43, therefore, 602 is not divisible by 43. If the result from step 2 is a multiple of 43, then the number is divisible by 43.

 

Learning the divisibility rule will help kids master division. Let’s learn a few tips and tricks for the divisibility rule of 43.
 

• Know the multiples of 43: Memorize the multiples of 43 (43, 86, 129, 172, 215, etc.) to quickly check the divisibility. If the result from the subtraction is a multiple of 43, then the number is divisible by 43.
   
• Use the negative numbers: If the result we get after the subtraction is negative, consider its 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 to check against divisibility.
  
  For example, check if 2581 is divisible by 43 using the divisibility test. Multiply the last digit by 9, i.e., 1 × 9 = 9.
  
  Subtract the remaining digits excluding the last digit by 9, 258 - 9 = 249. Still, 249 is a large number, hence we will repeat the process again and multiply the last digit by 9, 9 × 9 = 81.
  
  Now subtracting 81 from the remaining numbers excluding the last digit, 24 - 81 = -57. Considering the absolute value, 57 is not a multiple of 43. Hence, 2581 is not divisible by 43.
   
• Use the division method to verify: Students can use the division method as a way to verify and crosscheck their results. This will help them to verify and also learn.
   

• Divisibility rule: The set of rules used to find out whether a number is divisible by another number or not. For example, a number is divisible by 43 if the process outlined above results in a multiple of 43.
   
• Multiples: Multiples are the results we get after multiplying a number by an integer. For example, multiples of 43 are 43, 86, 129, 172, etc.
   
• Integers: Integers are the numbers that include all the whole numbers, negative numbers, and zero.
   
• Subtraction: Subtraction is a process of finding out the difference between two numbers by reducing one number from another.
   
• Absolute Value: The absolute value of a number is its distance from zero on the number line, without considering direction. For example, the absolute value of -57 is 57.