Divisibility Rule by 3

If the sum of all digits of a given umber is multiple of 3 or is exactly divisible by 3 then we can say that the given number is divisible by 3.

Lets take an example to understand this point more clearly.

Example - Is 543 divisible by 3?

Solution -

Let's sum the all digits i.e. 5 + 4 + 3 = 12.

Now we all know that 12 is divisible by 3 right? Hence 543 is divisible 3.

 

Example - Is 2861 divisible by 3?

Let's sum the all digits i.e. 2 + 8 + 6 + 1 = 17.

Now we all know that 17 is not divisible by 3 right? Hence 2861 is not divisible 3.

 

Point to be noted: It can be further added too.

Example - Is 845217 divisible by 3?

Let's sum the all digits i.e. 8 + 4 + 5 + 2 + 1 + 7 =  27 = 2 + 7 = 9

Now we all know that 9 is divisible by 3 right? Hence 845217 is divisible 3.


So to add further is more easier to know whether the number is divisible by 3 or not.

 

Do it by your self

Which of the following numbers are divisible by 3?

78451, 65844, 5694, 698754, 95356

 

Solution

78451 -7 + 8 + 4 + 5 + 1 = 25 = 2 + 5 = 7 hence not divisible by 3

65844 - 6 + 5 + 8 + 4 + 4 = 27 = 2 + 7 = 9 hence divisible by 3

5694 - 5 + 6 + 9 + 4 = 24 = 2 + 4 = 6 hence divisible by 3

698754 - 6 + 9 + 8 + 7 + 5 + 4 = 39 = 3 + 9 = 12 hence divisible by 3

95356 - 9 + 5 + 3 + 5 + 6 = 28 = 2 + 8 = 10 hence not divisible by 3

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Divisibility Rule by 2