Divisibility+Rules

Yesterday (Tuesday, October 5, 2010) we learned about divisibility rules. Divisibility rules are like little tricks to figure out if a number is divisible by a number. The numbers we learned about were; 2, 3, 4, 5 and 6. Below I will try to explain the rules for these numbers to the best of my ability.
 * 1) One is simple. Any number can divided by one.
 * 2) Two is pretty easy, too. If the number ends with an even digit, it can be divided by two.
 * 3) Three was a little harder. You add up all the digits of the number. So if the number is 32,001, you add up 3, 2 and 1 and get 6. 6 is divisible by 3, so 32,001 is divisible by three.
 * 4) Four involves memory. If the last digit in the number is even, the digit before it has to be either a 0, 4, or 8. If the last digit is odd, the digit before it has to be either a 2 or a 6. If these rules work with the number, it is divisible by four.
 * 5) Five is easy. If the last digit ends with a 0 or 5, it is divisible by five.
 * 6) 2 and 3 have to go into the number
 * 7) The easiest was is to just divide by7
 * 8) the last 3 numbers have to be divisible by 8
 * 9) the digits have to add up to a multiple of 9
 * 10) the number has to end in 0