I have two slide rules, actually; one from when I was in junior high school, which I turned up while clear out my mother’s house after her death; one that a friend gave me a decade or so ago as an antiquarian gift. I don’t use them much, but I did drag out the big one when I was doing some designs using GURPS Vehicles (which is physically realistic enough to use square and cube roots) and my scientific calculator had gone into hiding.

Long ago I saw the snarky comment that an engineer is someone who, asked “What’s two times two?” takes out a slide rule, fiddles with it, says “Three . . . nine . . . looks like eight . . . hmmm, where’s the decimal point go?”

Based on your description of the story, it sounds like a perfect combination of all the things Cory does really well. I’ve enjoyed everything of his that I’ve read. Now that I think about it I’ll bet his style is well suited to YA (is it a YA novel?), plus with his background at the EFF and elsewhere he’s well-suited to discuss issues like the erosion of civil liberties.

I’m of a generation too young for slide rules. But my technical training emphasized back-of the envelope calculations, so I can say confidently that 2×2 is approximately equal to 1 for small values of 2.