After reading this, you will be able to determine quickly, whether a certain number is divisible by a certain number (divisor) or not. You will learn the divisibility rules of 2, 3, 4, 5 and 6. For different divisors, the rules are different. Read them one by one and practice them as per exercise given. After a little practice you will be able to memorize all the rules.
Divisibility Rule of 2
If the last digit of any number is either 0 or even, the number will be divisible by 2.
For example 10, 34, 46 are even numbers hence they are divisible by 2 but 3, 13, 99 are odd numbers hence they are not divisible by 2.
Exercise: Check whether the following numbers are divisible by 2 or not?
23, 34, 73, 39, 167, 200
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Divisibility Rule of 3
If the sum of all the digits of a number is divisible by 3, the number will be divisible by 3.
For example the sum of all the digits of number 123 is 6 (1+2+3). Hence 123 is divisible by 3.
Exercise: Check whether the following numbers are divisible by 3 or not?
3, 13, 23, 34, 73, 39, 122, 129, 167, 200
Divisibility Rule of 4
If the last two digits a given number is divisible by 4, the number will be divisible by 4. Also if the last two digits of a number 00 the number will be divisible by 4.
For example the the last two digits of 112 are 12, which is divisible by 4. Hence the number 112 will be divisible by 4.
The number 10000 will be divisible by 4 because the last two digits are 00.
Exercise: Check whether the following numbers are divisible by 4 or not?
10, 20, 114, 225, 346, 673
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Divisibility Rule of 5
If the last digit of a number is either 0 or 5, the number will be divisible by 5.
For example the last digit of 75 is 5, so it is divisible by 5. The last digit of 33 is neither 0 not 5, so it is not divisible by 5.
Exercise: Check the divisibility of following numbers by 5.
10, 20, 23, 34, 73, 39, 114, 225, 346, 673
Divisibility Rule of 6
If a number is divisible by both 2 and 3, the number will be divisible by 6.
For example the number 66 is divisible by 2 (as last digit is even) as well as by 3 (the sum of all digit is 12, which is divisible by 3), so it is divisible by 6.
The number 76 is not divisible by 6 because it is divisible by 2 (last digit is even) but not by 3 (sum 13 is not divisible by 3).
Exercise: Check the divisibility of following numbers by 6.
10, 20, 23, 34, 39, 73, 39, 39, 114, 225, 346, 673, 12273
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