Divisibility Rule of 28

The divisibility rule for 28 is a method by which we can find out if a number is divisible by 28 or not without using the division method.

Check whether 196 is divisible by 28 with the divisibility rule.

Step 1: Check if the number is divisible by 4. The last two digits of 196 are 96, which is divisible by 4.

Step 2: Check if the number is divisible by 7 using the divisibility rule of 7. For 196, multiply the last digit by 2 (6 × 2 = 12) and subtract it from the remaining digits (19 - 12 = 7), which is a multiple of 7.

Since 196 passes both conditions (divisible by 4 and 7), it is divisible by 28.

Learn divisibility rules to help kids master division. Let’s learn a few tips and tricks for the divisibility rule of 28.

• Know the multiples of 28: Memorize the multiples of 28 (28, 56, 84, 112, 140… etc.) to quickly check the divisibility. If the number matches any of the multiples, it is divisible by 28.
   
• Use negative numbers carefully: If the result obtained during the process is negative, consider it as positive when checking for divisibility.
   
• Repeat the process for large numbers: Students should keep repeating the divisibility process for both 4 and 7 until they reach a small number that is divisible by both.
  
  For example, check if 392 is divisible by 28 using the divisibility test. 
  
  First, check for divisibility by 4: The last two digits are 92, which is divisible by 4.
  
  Next, check for divisibility by 7: Multiply the last digit by 2 (2 × 2 = 4) and subtract it from the remaining digits (39 - 4 = 35), which is a multiple of 7.
   
  Since 392 satisfies both conditions, it is divisible by 28.
   
• Use the division method to verify: Students can use the division method as a way to verify and crosscheck their results. This helps them verify and also learn.

• Divisibility rule: The set of rules used to determine whether a number is divisible by another number without actual division.
   
• Multiples: Multiples are the results we get after multiplying a number by an integer. For example, multiples of 28 are 28, 56, 84, 112, etc.
   
• Integers: Integers include all whole numbers, negative numbers, and zero.
   
• Subtraction: Subtraction is a process of finding the difference between two numbers by reducing one number from another.
   
• Verification: A method used to confirm the accuracy of a result, such as using division to check divisibility.