But surely in math, of all subjects, it's easily possible to construct problems that cannot be solved without thinking and understanding, that do not reduce to mere memory and recognition of a known question "5x5". Then students who want the "right" answer will be forced to understand.
This isn't absolute, of course. When learning elementary multiplication, pretty much all you can ask about is multiplying, and there are only a few dozen pairs in the 10x10 multiplication table, and students generally just remember them, they don't calculate. But by the time you're up to arbitrary size multiplication or long division, you need to apply an algorithm; that's a step of understanding, because you can see that the algorithm also produces the results you memorized earlier. And so on.
When students are at the 5x5 level, I don't think there is an answer to "why is 25 the right answer?" that they could understand - it just is the right answer, a brute fact about life, just like the sky is blue and sun comes up every day. But that doesn't continue forever.
In my personal experience schools go way too far in the other direction, and keep asking for rote memorization when it's already possible to ask for understanding.
That depends on the level of explanation the teacher requires and the level of the material. I'd say that at least until you get into calculus, you can work off of memorizing answers. I'd even go so far as to say that most students do, and succeed to greater or lesser degrees, based on my tutoring experiences. I am not sure to what degree you can "force" understanding: you can provide answers that require understanding, but it helps to guide that process.
I went to a lot of schools, so I can contrast here.
I had more than one teacher that taught me...
As a teacher, I wonder if it is possible to instill this skill into students the skills of rationality and critical thinking. I teach the third grade, and it is not immediately apparent how to apply this with my own class.
The problems I foresee are as follows:
In the sequences, it is suggested teachers should drill into students words don't count, only anticipation-controllers. How practical is this for an elementary school level? Also appreciated would be any ideas or experiences on how to do this, or how to combat the above problems. Hearing from other teachers would be excellent especially.