Someone (perhaps Kriston???) in passing I believe, mentioned Murderous Maths. I ordered one.

A week ago, I was thinking about numbers and wrote the numbers 1-10. I then, for some reason, wrote the squares of those numbers. I then noticed that the difference of the squares was 3, 5, 7, 9 etc and therefore the difference between those is 2! I thought, hhmm, isn�t that fascinating! I know, many of you are thinking "She's just now getting that?" But I suppose better late than never. So I turn the page in �Murderous Maths� and I see what I had written, laid out right there! So I told DS of my doodlings in math, and we read through the chapter in the book together. It was cool to read the reasoning behind (xsquared-ysquared)=(x+y)(x-y) algorithm is the natural extension of what I was doodling. I like how it uses plain old counters to illustrate the concepts. Now perhaps I did learn the whys in school and have just forgotten but it was great fun discovering or re-discovering it, as the case may be.