## Wednesday, July 02, 2008

### math post #7 (probably)

It's still just mostly incomprehensible scratchings to me.

I think I must be in a weird place. I do well at whole number, basic math, which is why I didn't go into MTH10. But I'm struggling with MTH20, which is probably the equivalent of high-school pre-algebra.

I work on a concept, work on applying the concept (through the problems and study guides in the book), then flail stupidly when actually doing the problems and come up with answers so far off the mark I can't even imagine what the fuck I was thinking or where it all went to shit.

When I do my homework and check it over on my own, I'll still come up with 10-15 wrong out of 40 when we go over it the next day. If the Smart Half goes over it with me after I'm done, I get maybe 3-5 wrong. So I am having him go over it with me. I don't see the mistakes. Because I don't understand it.

We're heading into complex fractions right now. And, it's like, crap... all these numbers and lines and rules and if it's negative you do this and if it's two negatives you do this and to divide you flip and multiply and make it small and ok well you lost me there. I really pay attention in class. I write all the rules down on their own page and look at them before I start homework.

I think I get it for 30 seconds and then nothing makes sense.

But I'm going to pass the damn class.

1. What math book are you using? Just curious as I'm teaching my 5th grade son with autism pre-pre algebra and I use SRA Direct Instruction. The instruction is so clear, with plenty of practice and slow build up of skills that it simply works.

They keep the success rate over 90% correct or the teaching has problems (not the student). You might need to figure out what your specific problem is: for instance - do you know your math facts well? If so, are you not able to follow the rules/formulas? Is the curriculum not building the skills in a slow, discrete method to where there are holes?

Just wondering. Math is fun and wonderful, when taught well.

2. I can't hold the stuff in my head while I work a problem out. Like, I forget halfway through the problem what I was doing with the numbers..how to do what i was doing with the numbers. On every problem. Relearning the order of operations has helped a lot, but there's still a big sieve in my brain pan.

Not sure what the book is called, offhand. It's in the other car :P Basic Math for College Students or something like that.

3. Pril, does the text explain why the rules work, or does it just say "here are the rules, now go do them"? It becomes a lot easier to apply math rules if you know why the rule is set up that way.

One way to think through the "to divide you flip and multiply" is to start with a simple case: dividing by 1/3 is the same as multiplying by 3, and dividing by 2 is the same as multiplying by 1/2. That's a simple example of flipping over.

Now suppose you want to divide by 2/3. Because 2/3 equals 2 times 1/3, that's the same as dividing by 1/3 and then dividing by 2. (I wish I had a blackboard.) Dividing by 1/3 is the same as multiplying by 3, and dividing by 2 is the same as multiplying by 1/2. Because 3 times 1/2 equals 3/2, dividing by 2/3 is the same as multiplying by 3/2. The books, alas, often give us the rule, but don't explain why it works.