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It sounds like he's just talking about using variables to solve equations. I think the point he's making in that section is just about learning a good process so you can solve harder and harder problems, e.g. Problem 1: Two numbers add to 100, one is 20 larger. Smart student: oh, I see, 60 and 40. Dumb student Knuth: x + y = 100 and x = y + 20, solves to x=60, y=40. .. Problem 2: Four numbers sum to 1024, one is half the sum of the other three less 17, one of the others... Smart student: uh, I don't see the answer. Dumb student Knuth: w + x + y + z = 1024, w = (x + y + z)/2 - 17, ... solved it. |
So I second OP's comment - I wish there were a course one could take on algebra itself - not merely numeric expressions with variables.