Which numbers are divisible?
2 For a number to be divisible by 2, for example, it has to be even. Numbers such as 8,10, 64, and 2, 368 are divisible by 2; 5, 67, and 103 arent. So you can tell whether a number is divisible by 2 just by looking to see if its even. You dont actually have to do the division. 3Deciding if a number is divisible by 3, however, isnt so obvious. Take 144, for example. You cant tell just by looking whether 3 will go into 144 with no remainder or not. You could find out by dividing, but theres another way. To test if a number is divisible by 3, add up the digits in the number youre testing. Is that sum divisible by 3? Take 144, for example: If you add 1+4+4, you get 9. Since 9 is divisible by 3, so is 144. This test is useful for large numbers such as 273, 645. Add the digits: 2+7+3+6+4+5. The sum is 27. Still not sure? Then add the 2 and the 7. That should convince you. 4For divisibility by 4, you can test by looking at the last two digits of the number youre testing. If that number is div
