No
Yes. You can always tell if a number is divisible by 4 by looking at the last 2 digits. In this case, 36 (4 times 9) is a multiple of 4, so 3736 is also. This is because the difference between a number and the last 2 digits (in this case, 3700) is always a multiple of 100, which is a multiple of 4.
The sum of any two-digit number and the number formed by reversing the digits is always divisible by 11. This is because when you add a two-digit number to its reverse, the result will always be a multiple of 11. This is because the difference between the original number and its reverse is always a multiple of 9, and when you add two multiples of 9, the sum will always be a multiple of 11.
63
It doesn't. It's not true.
13
No. However, one you you can tell is that the digits of a multiple of 3 always add up to another multiple of 3.
no, it matters with the number not digits
No For example, 16 is a multiple of 4 but ends in a 6. 20 is a multiple of 4, but ends in 0. To check to see if a number is a multiple of 4, see if the last two digits are a multiple of 4 or '00'. If the last two digits are a multiple of 4 or are '00', the entire number is a multiple of 4.
21
No. To find if a number is a factor of 3, add the number's digits. If the resulting number is a multiple of 3, then the original number is a multiple of 3. In 4339, the digits of the number added together is 19, which is not a multiple of 3.
300, 600 and 900.
A number is divisible by 3 if the sum of its digits is a multiple of 3. A number is divisible by 6 if the sum of its digits is a multiple of 3 and it's even. A number is divisible by 9 if the sum of its digits is a multiple of 9.