In school, I was OK in math and even (somewhat) enjoyed it; yet, I didn’t have any interest in taking anything more than the required classes in high school and when I did complicated operations I HAD to write out every single step or else I would get confused. There were many things I really didn’t understand about math – I just memorized the steps one is taught to go through to solve the problem. I would often have a hard time wrapping my mind around what I was supposed to do or why this or that happened because I didn’t fully understand the WHY behind it.
Take, for example, the relatively simple, yet seemingly complex, aspect of “borrowing” in subtraction. Am I the only one who was eternally confused by borrowing? I “got” how you were supposed to do it – you slash through this one little number and write this other number above it, then continue with the problem – but I didn’t know what it meant. Never did a teacher try to explain it to me; I was shown how to do it and then told to practice. Because I didn’t really understand what I was doing, I disliked any problem that involved borrowing and used a calculator as soon as we were “allowed” to.
Read more here: https://www.mariamontessori.com/2011/01/09/finally-understanding-math/