Divisibility Rules - Divisible or Not Divisible?

Divisibility Rules - Telling Right Away if A Number is Divisible by 2, 3, 4, 5, 6, 9 and 10

Divisible means a number completely divide another number and gives zero remainder. We can tell very easily that if 2 or 3 or 5 will completely divide a given number without doing the long division.

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Below are the Divisibility Rules (tests) starting at the test for divisibility by 2 and ending at test for divisibility by 10:

Divisibility test for 2: Any number with 0, 2, 4, 6, 8 at their ONES PLACE is divisible by 2. For example; numbers 228, 1594, 5002 and 1170 have 8, 4, 2 and 0 at their ONES PLACE respectively, hence all of these numbers are divisible by 2.
Divisibility test for 3: Add all the digits of the given number and if the sum is divisible by three then the given number is also divisible by three. Consider there is a number 7023. To test for divisibility by 3 add all the digits of the number (7 + 0+ 2 + 3 =12),we get 12 as the sum of digits and which is divisible by 3, hence the given number 7023 is divisible by 3.
Divisibility test for 4: Look at the TENS and ONES digit of the number to get a two digit number and if this number is divisible by 4 then the given number is divisible by 4. For example; consider the given number is 25424 and the TENS and ONES digits (last two digits at far right) make 24 and which is divisible by 4, hence 25424 is divisible by 4.
Divisibility test for 5: If the ONES digit of the given number is “0” or “5” then the number is divisible by 5. For example; consider the given number is 30085, as the ones digit is 5, hence 30085 is divisible by 5
Divisibility test for 6: A given number is divisible by "6" only if it is divisible by both "2" and "3". Consider the given number is 516. This number is divisible by 2, as the ONES digit is 6 which is divisible by 2. Now add the digits (5 + 1 + 6 = 12) to get 12 and which is divisible by 3, hence the number 516 is divisible by 3 too. As 516 is divisible by both 2 and 3 hence it is divisible by 6 as well.
Divisibility test for 9: Add all the digits of the given umber and if the sum is divisible by 9 then the number is divisible by 9. Divisibility tests for 3 and 9 are identical.
Divisibility test for 10: Simplest of all. Look at the ONES digit of a number and if it is zero then this number is divisible by 10. For example; 350 has “0” at ONES place, hence it is divisible by 10.

There are divisibility rules for 7 and 8 as well but I think that's too much. If students in grade 6 or 7 just know the divisibility by 2, 3, 5 and 10 they can achieve very good marks and be very successful in higher grades math.