Gazinta January
As in, 11 gazinta 99, but 8 doesn’t ga’inta 23.
January math posts will deal with divisibility. We will look at
- what divisibility means
- division and long division
- checking divisibility without dividing
- divisibility rules (base 10)
- divisibility rules (other bases)
- teaching tips and tricks,
- and of course, little puzzles along the way.
Let’s start: When we talk about divisibility, we’ll be talking about whole numbers only. I will write “number” and we will understand that we are only discussing positive integers. These topics won’t make sense for fractions or decimals or square roots… We won’t talk about negative numbers either. And we’ll set aside some time to briefly discuss zero and division.
We can say 3 goes into 15, or we can say 3 divides 15, or we can write 3|15. All of these mean that there is some number (no mystery here, it is 5), but in general some number, such that 3 times the number is 15. Remember, number means positive integer in these posts.
We can say that 2 does not go into 17, or we can say 2 does not divide 17, or we can write 2∤17. All of these mean that there is not a number we can multiply 2 by to make 17. (Eight and a half? Remember, we are talking about whole numbers. Fractions don’t count).
JD2718 
*groaning* I’m not sure if I’m looking forward to this or not. :)
Happy New Year!
Tsk, tsk, all good stuff.
There are a bunch more divisibility rules than we generally teach.
There’s more than one way to do long division.
And there are strange ways to test divisibility using neither of those.
Plus, puzzles.
How bad could it be?
Nice snow. Since my Seventh grader is doing some divisibility work on some level, I’ll tag along for awhile. Hopefully you will have manipulatives, visual aids, and charts and graphs. I would like your take on “fuzzy math.”
see http://michellemalkin.com/2007/11/28/fuzzy-math-a-nationwide-epidemic/
You want manipulatives? Or you want Michelle Malkin Math? I think they are mutually exclusive.
Actually, I am quite critical of the “progressive” curricula, but I think that many of their activities, taken singly, can enrich a traditional curriculum.
As for the divisibility series, you can look forward to mostly numbers and algebra, some diagrams, and my specialty, puzzles. Afraid there won’t be neat graphs. On the other hand, I think that it will be engaging.
WordPress gave us snow for a little while, so I put it here.
http://wordpress.com/blog/2007/12/25/let-it-snow/
Jonathan
I am no fan of manipulatives. The public schools here in Austin had my kids drawing pictures, using beads and what not, or anything else besides using real numbers to solve math. Kids now in private school that, to my knowledge, avoids those methods.