> Why do we teach kids how to do basic arithmetic by hand?
I think kids waste way too much time doing hard arithmetic by hand. As a particularly egregious example, I visited a Montessori primary school where they demonstrated what is essentially a complex single player board game, for calculating square roots by hand. It's a process whereby a 5th grader would take ~10 minutes to calculate the root of a 3 digit number, by moving dozens of pins around. It looked so silly, and while other Montessori equipment offers geometrical intuition, this one seemed to offer none. Squaring with trial and error would have been so much easier.
Other more typical examples are of kids spending hundreds of hours practicing long multiplication and long division of e.g. 4 digits, and then getting punished and stressed out about having made silly mistakes. While in the real world, no one in their right mind would choose to perform these calculations by hand any more, and would instead use a tool incapable of making arithmetic mistakes.
I don't have a clear solution, but would tend towards an educational system that teaches only the very basics of performing each mathematical operation (probably up to the level the average literate adult would do mentally), and then focus the rest of the time on problems where the students are the ones posing the question, using a calculator/computer to solve it, and then check whether the answer makes sense in the original context.
EDIT: For those curious about it, I just found a blog post demonstrating the logic behind this square root peg board. The author of the blog argues that it does help build understanding, but from what I saw, I would politely disagree.
https://borisreitman.medium.com/square-roots-the-montessori-...