Exactly. And as a future engineer, I find it to be a very attractive facility to have. The techniques even lend themselves to integration. After plugging in the limits of integration, mental math could make the evaluation process very quick (I imagine).
That was my suspicion.
You said that you would recommend that I memorize squares. How far up should I memorize them? I read somewhere that 30 is a good point. Would you agree?
That makes sense. Calculate squares using shortcut methods, then step up or down until you reach the target number.
Awesome! I’ll keep an eye out for it.
I’ll probably give it a try. I can already add/subtract quickly, but it’d be really cool to learn to add/subtract 4 or 5 digit numbers in a couple seconds. Hopefully that will be achievable. I’ll probably start with around 20 minutes/day, and then I’ll see where I am in 3 years or so. I guess it could only help.
Thanks again for all your time, Kinma. I really appreciate it. 