[swatcoder]

For a senior-level professional? Yes, it does matter.

I wouldn't be comfortable with an accountant who couldn't do practical arithmetic in their head, or a surveyor who didn't have a fluent grasp of trigonometry and the ratios or function values for common angles.

Of course -- I don't care about the people working for them as a bookkeeper or assistent. They can be button monkeys as much as their boss lets them, but I also wouldn't expect those folk to reach very high in their career. Not everyone's going to, and a disinterest in and lack of technical fluency is a darn good predictor.

Your teacher was giving good advice about building skills and internalizing knowledge, because those are what contribute to mastery of a craft; maybe you were just being too pedantic or cynical to hear it?

[wruza]

I think this advice is backwards, as is the problem. I’d trust an accountant’s mind or a builder’s eye if I knew that they are acting from experience. But you don’t wanna trust someone who believes in-their-head is superior or reliable and makes you good.

The core idea is no, calculating in your head doesn’t turn you into a pro. Being a pro makes calculating in your head safe enough to rely on until you get to your desk and double-check.

That said, I was an integrator half my life and seen some accountants, big and small. Everyone used a calculator, it’s right next to their mouse and there’s another one elsewhere. And no one ever tried to talk about numbers afk, except for ballparks. Most of the times they suggest to go and query a db together. I find it very professional.

[grobgambit]

I just trust my accountant will use excel and what they are doing isn't rocket science.

I have no interest interacting with someone who is going to get into how great the slide ruler is and how kids these days need to learn the slide ruler. When I was younger I thought this type of person was highly admirable but now older and wiser I see how full of shit they are.