DIVISIBILITY RULES

7

Sorry, no divisibility rules for 7 have been discovered.

6

A number is divisible by 6 if it is divisible by 2 AND it is divisible by 3. For example, 8,634 is divisible by 6 because the number is even and so it is divisible by 2. Also, when you add the digits of the number 8,634 (8+6+3+4), you get 21. 21 is divisible by 3 and so the number 8,634 is divisible by 3. So, since 8,634 is divisible by both 2 & 3, then it is divisible by 6. Test it if you want, but it will always work. It's unbelievable.

10

A number is divisible by 10 if the last digit is 0.

2

A number is divisible by 2 if it is an even number. The last digit must be 0, 2, 4, 6 or 8.

3

A number is divisible by 3 if the sum of the digits is divisible by 3. For example, the number 8,634 is divisible by 3 because when you add the digits of the number 8,634 (8+6+3+4), you get 21. 21 is divisible by 3 and so the number 8,634 is divisible by 3. Test it if you want, but it will always work. It's magic.

4

A number is divisible by 4 if the number formed by the last two digits is divisible by 4. For example, the number 4,765,432 is divisible by 4 because the last two digits make the number 32. 32 is divisible by 4 so the number 4,765,432 is divisible by 4. Test it if you want, but it will always work. It's amazing.

5

A number is divisible by 5 if the last digit is either 0 or 5.

8

A number is divisible by 8 if the number formed by the last three digits is divisible by 8. For example, the number 4,765,432 is divisible by 8. How can you tell? Well, the last 3 digits forms the number 432. If you divide 432 by 8 you get 54 with no remainder. So the number 4,765,432 is divisible by 8. Test it if you want, but it will always work. It's absolutely freaky.

9

A number is divisible by 9 if the sum of the digits is divisible by 9. For example, 8,634 is not divisible by 9 because when you add together the digits of the number 8,634 (8+6+3+4), you get 21. 21 is not divisible by 9 and so the number 8,634 is not divisible by 9. However, the number 8,631 is divisible by 9 because 8+6+3+1 is 18. 18 is divisible by 9 so the number 8,631 is divisible by 9. Test it if you want, but it will always work. It's miraculous.