Teaching Textbooks Placement

[frogger]

I have a nine soon to be ten year old that hasn't had a lot of formal math. We have tried some curriculum but usually drop it after a little while. The reason I'm telling you this is to explain why a placement test will be of no help. He has very little ability to memorize but if a subject is explained or if he simply figures it out on his own then he knows it and will never forget it. He figured out how to divide fractions (not necessarily on paper though) when we were dividing a large recipe one day. I never explained it he just figured it out on his own. So just because he hasn't been exposed doesn't mean he won't catch on easy. I'm wondering whether to start him in Teaching Textbooks 4,5, or 6.

I have heard that Teaching Textbooks run easy. If you have used Teaching Textbooks do you find this to be true? The sample lectures seem very easy to follow but often beginning lessons are easy and then authors seem to get impatient and everything gets hard all at once at the end. Have you noticed this with Teaching Textbooks? Also if you have chosen the "starting math late" method your insights would be well appreciated.

Thanks for any insights or experiences.