Divisibility War

Last week, Alex was working on divisibility rules. Here are the rules we were working on:

• 2's - if it ends in 0, 2, 4, 6, or 8, it is divisible by 2
• 3's - add the digits and if they are divisible by 3, the whole number is divisible by 3
• 4's - if the last 2 digits of a number are divisible by 4, the whole number is divisible by 4
• 5's - if it ends in 0 or 5, it is divisible by 5
• 6's - if it is divisible by both 2 & 3, it is divisible by 6
• 9's - add the digits and if they are divisible by 9, the whole number is divisible by 9
• 10's - if it ends in 0, it is divisible by 10

I went online and found this Divisibility War game. Basically, I wrote down some of the numbers from their list and dealt us each out 6 cards. We took turns going through the cards and deciding if they were divisible by each of the following: 2, 3, 4, 5, 6, 9, & 10. For every number that it WAS divisible by, we put a marker on the card. At the end of the game we saw who had the most markers.

After we'd played it a couple of times, I changed the rules a bit. Now, if Alex makes a mistake (or I do!), I will challenge her and "get" her point. This makes sure she is really paying attention (and that I am, too).

She has really liked this game and keeps asking to play it. It is a great way to reinforce divisibility rules!