Absolutely correct, but it's worse, since they don't truly understand math, they taught in such a way that confused/misled students, no wonder USA had to import

Absolutely correct, but it's worse, since they don't truly understand math, they taught in such a way that confused/misled students, no wonder USA had to import so many STEM engineers(and graduate students to fill college classrooms) from other countries, and it's getting worse. The fix is to have specific teacher undergraduate or graduate degree, or education departments or state-funded full-blown normal universities, pay them well, make teacher profession a honorable career, only then the best will seek a position in k-12 schools and our next generation can keep getting better.