[mph10]

Subtraction is not necessary for division.

This is a specific example, and the general point is that there a multiple ways of doing things. If a child can avoid 1 step and skip straight to the result more efficiently, that is a valid way of solving a problem.

[sudosysgen]

Substraction is necessary for long division. Elementary schools force you to learn long division because later when you learn algebra, you need long division to divide polynomials, for example. You also will need substraction to do Gaussian elimination, etc...

Many school systems make difference between the ability to solve a problem, and the ability to solve a problem a certain way. Sometimes the first is all that's asked, but when that way of doing things is necessary later, then the second is asked of you.

The point is that you want to prepare the child for what they will need in the future. Sure, perhaps you are doubly exceptional and will be able to adapt on the fly in the future, but you can't design a school system around extremely uncommon students.

I say this as another 2E student that had very similar issues. There is no good way of fixing it except maybe by giving special accommodations to these students. I repeatedly failed exams exactly because I would skip steps this way, but there is no sense fundamentally changing the entire school system and hurting the majority for that.