It is/was, but the Common Core Math standards are trying to change that. Children are now being taught how to look at addition, subtraction, multiplication, division, fractions, and other concepts from a variety of perspectives. Predictably, it's driving their parents insane because they were taught the "one true algorithm" for each of these tasks and can't help their kids when confronted with alien algorithms that change from semester-to-semester.
Real math is about being able to derive this stuff when woken up at 5AM.
What you get in school is drilling kids to appear as if they understood math so that adults who don't remember this stuff anymore feel intimidated and leave with impression that their children are learning some rocket science and the "education system" deserves their money.
No teacher literally reasons like that and no one will tell you that, but that's exactly what they do when they are overwhelmed by a horde of barely interested kids who somehow have to pass the final exams. The other part of this insanity being politicians who set up those exams.
People who understand math can do X, Y, and Z.
Therefore we should make sure children can do X, Y, and Z.
Then they'll understand math too!
A majority of it is memorisation, which makes it both very easy in some respects, and hard in others. I still feel in the end it is a bit useless to learn it in the way we do now, seeing as computers can do it in a fraction of a second.
Well, I enjoy maths, but for me my entire mathematical education was always about memorizing tables. It was made worse by the fact that during Polish exams you cannot use advanced calculators(only ones that can do addition/multiplication) so for the final exams at the age of 19 I had to remember loads of different formulas, trigonometric values for common angles etc etc.
I'm not saying he was wrong, but in a lot of educational systems maths is 90% about remembering stuff.