I learned math long after the advent of the calculator and went on to study math-heavy fields (physics, mechanical engineering, and data science).

I wasn't ever able to really develop deep intuition about/understanding of a calculation until I did it by hand once or twice. I often just plugged in new models and algos just to see if performance was above a threshold, but when I wanted to productionize a new winner, I'd have to run through the algo by hand for a few steps to understand and tune it. And through doing it by hand, the complex became the simple.

I am not expert, but I heard brains learn way better when we actually use our hands to write stuff out.

like the logic sticks deeper in your head that way... using computer is fast, but sometimes it just goes in one ear and out the other