While these are simple tricks almost everyone here knows, there are great books on advanced techniques. I heard about this one from a math blog and got it. Goes into gory detail about to manually calculate logs and roots, reciprocals and transcendentals. It was a fascinating read, I expected it to help me sleep at night and it did the opposite.
All those things are true. ;) And the author admits them in the introduction, which you should be able to read from the amazon page. It is still an amazing book. A lot of the reviews clearly expected this to be a way to learn quick tricks to impress their friends. There are lots of books like that, but this isn't one of them, this one goes deep into the theory and long lost methods for doing difficult problems without a computer. For this audience, the difficulty level will be mixed and not necessarily all hard. Anyone who's done some programming will find plenty of material that is both accessible and super interesting.
"Dead Reckoning: Calculating Without Instruments"
https://www.amazon.com/gp/product/0884150879/