Divisibility Rule of 39

The divisibility rule for 39 is a method by which we can determine if a number is divisible by 39 without using the division method. Check whether 1521 is divisible by 39 with the divisibility rule.  

Step 1: Separate the number into two parts. For instance, in 1521, separate it into 15 and 21.

Step 2: Check if both parts (15 and 21) are divisible by 3. Since 15/3 = 5 and 21/3 = 7, both parts are divisible by 3.

Step 3: Check if both parts (15 and 21) are divisible by 13. Since 15 is not divisible by 13 but 21 is, the number is not divisible by 39.
 

Learning the divisibility rule helps kids master division. Let’s learn a few tips and tricks for the divisibility rule of 39. 

• Know the multiples of 39: Memorize the multiples of 39 (39, 78, 117, 156, etc.) to quickly check divisibility. If both parts are divisible by 3 and 13, then the number is divisible by 39.
   
• Use the parts method: If dealing with a large number, break it into smaller parts and check each for divisibility by 3 and 13.
   
• Repeat the process for large numbers: Students should keep repeating the divisibility process until they can easily determine if each part is divisible by 3 and 13. 
  
  For example, check if 5079 is divisible by 39 using the divisibility test. Split into two parts: 50 and 79. Check: 50 is divisible by 5, but not by 3 or 13. 79 is not divisible by 3 or 13. Since neither part meets the criteria, 5079 is not divisible by 39.
   
• Use the division method to verify: Students can use the division method to verify and cross-check their results. This will help them verify and also learn.
   

• Divisibility rule: The set of rules used to determine whether a number is divisible by another number, such as 39.
   
• Multiples: Results obtained by multiplying a number by an integer. For example, multiples of 39 are 39, 78, 117, etc.
   
• Integers: Numbers that include all whole numbers, negative numbers, and zero.
   
• Separation: The process of dividing a number into parts to check divisibility.
   
• Verification: Using calculations, such as division, to ensure the correctness of the application of divisibility rules.