Tip

How can you tell if a number is divisible by four? If the last two digits of the number are divisible by four then the original number is also divisible by 4. For example, if the number is $47,128$ then the last two digits of that number is 28. As 28 is not divisible by 4 the original number $47,128$ is not divisible by four. Why Does This Method Work? The reason why this method works is that the multiples of four reset at every hundred. Therefore, if you start at four and progress by 4’s you’ll hit 100. ...

How do you know if a number is divisible by three? The fastest way of determine if a number can be divisible by 3 is to add up all the digits in the number and if that number is divisible by 3 then the original number is divisible by 3. For example, suppose the original number tested to see if it can be divisible by 3 is the number $1,234$. ...