Earlier quoted context omitted.
This is a sort of mental math trick that isn’t incredibly useful in day to day engineering. Now if they say 16,000 or something then maybe there’s an argument against them, but being able to calculate a tip on the fly isn’t really something worth selecting for imo
It's not a "trick". And yes, it's incredibly useful in enabling recognizing when your calculator gives a bogus result because you made a keyboarding error. When you've got zero feel for numbers, you're going to make bad engineering decisions. You'll also get screwed by car dealers every time, and contractors. You won't know how far you can go with the gas in your tank. It goes on and on. Calculators are great for get…
It might be counterintuitive, but the cheaper (and therefore successful) solution will always be more technological integration, not less.
In this case, better speech recognition, so the user doesn't have to type the numbers anymore, and an LLM middleman that's aware of the real-world context of the question, so the user can be asked if he's sure about the number before it gets passed to the calculator.