I said back in mid-September that Sean wasn't too interested in the Murderous Math books that Brian used to love so much. Right after we returned to Moscow from Singapore in mid-January, he started reading the entire series every day. He's read many, if not all, of the books at least 3 times. I'm sure he understands only bits of the books, but that's the beauty of these books, kids enjoy the comics first, and learn more and more each time they re-read the books, without ever realising that they're learning. The best kind of learning, in my opinion.
After reading the books, Sean would draw, make things (eg make shapes out of paper) or find things in real life that he feels are related to what he's learnt from the books. I don't remember Brian doing much of this in the past. I think it's Sean's way of internalising what he's read and reinforcing his understanding.
Pythagoras Theorem illustrated. He's just drawing what he's seen from the book, it doesn't mean he really understands how to use the formula.
And here he's tri-secting (I don't think tri-secting's the right word but that's what he said he was doing) regular polygons, from 3-sided ones to nine-sided ones. He offers this nugget, "The more number of sides the shape has, the smaller the central angle will be."
And one day, he came by with these two blocks and points to the semicircular bit and tells me it was a Reflex Angle (an angle more than 180 deg but less than 360 deg).
He spends hours using the protractor, drawing angles, folding paper, cutting out shapes (yes, he's been left alone a lot the past month, I was sick lah). For some time, he kept bugging me for a UK 50p coin cos Brian had told him it was the shape he (Sean) was looking for, a heptagon.
I couldn't find him a 50p coin and was still not sure if it was really a heptagon till I googled it 10 seconds ago. True enough, 7 sides. Not many coins with 7 sides right? Must remember to keep a 50p coin for Sean next time I'm in London.
While I was typing this, Sean came by to ask, "If each side of an equilateral triangle was 33cm, how many 3cm equilateral triangles would fit in it?" Upon drawing the big and small triangles, we then find out it's 121 triangles, ie the 11th (33/3) square number. So if the big triangle was 48cm-sided, and the small triangles were 2cm-sided, it'll just be the 24th (48/2) square number, ie 576 small triangles would fit into the big triangle.
MM books put many mathematical concepts within the grasps of primary schoolchildren. Heck, it's useful for adults too, since we never learnt many of these in school, at least I didn't. I thought I learnt quite a lot when Brian was using the books cos he would tell me all the interesting things he had read, but this time round, I'm learning more new stuff too with Sean cos he learns in such a different way from Brian. It probably helps that I've had 1 round of MM with Brian, so some of the basics have been covered, and I'm not as clueless as before.
Kjartan Poskitt is truly my hero, math-wise, that is. I just wish he'd write an MM book on Calculus soon.