The actual training teachers are receiving is that there are many ways to teach things like long division, and insisting on only using one method is not useful to students.
As an example, when teaching multiples of 9 you shouldn’t just use rote learning but point out the internal checksum of multiples of nine (add up all the digits to get a single digit and you get 9, for the simple tables the first digit will be 1 less than the number being multiplied, so 4 x 9 is 36, 3 + 6 is 9, 5 x 9 is forty-something so working backwards 9 - 4 is 5, so 4 x 9 is 45).
In addition there’s the “times ten minus one” method: 3 x 9 is the same as 3 x (10 - 1) so 30 - 3 is 27 (and add up the digits to make 9).
Teachers need to be allowed to use multiple methods of instruction, and restricting them to only exactly what is in the syllabus is racist because then the only people who get the quality instruction are the rich who can afford out of school tutelage, ie: predominantly white populations due to institutionalised racism in the USA keeping non-white populations poorer than their mostly white neighbours. Yes, there are white people living in poverty but when you compare white to non-white populations in the same region they are still better off.
The shorthand in the USA is that any policy which keeps poor people from success is racist because the rich/poor divide in the USA is predominantly along racial lines.