a number is divisible by 12 if the number is also divisible by both 3 and 7. You mean a number is divisible by 21 if it is divisible by 3 and 7.
Chat with our AI personalities
A divisibility rule is a statement of procedures to determine divisibility. For example:"A number is divisible by 2 if it ends with 0, 2, 4, 6 or 8".It does not make any sense to divide such a sentence by 2 or 895 or any other number!
2.50
For any practical purpose, it is easier to simply divide, instead of looking for fancy divisibility rules. However, you can apply the divisibility rules for 3 and for 7. This works because (a) their product is 21, and (b) these numbers are relatively prime.
There is no divisibility rule for 13 because it is a prime number. If you are thinking: why is there a divsibility rule for 2 and 3 then. Well, i don't know so go look it up on google.
It is 3 6 9