Have to agree here. There are some shocking teachers. All through my schooling career I was an ace student and maths and sciences. I put tons of effort in. I grew up with my dad being able to multiply any two, four digit numbers together quicker than you could punch it out on a calculator. Maths was a passion for me, inspired by my ubringing. I never got below 90% until grade 11. In grade 11 my maths went from 90% to 65% in one year. The following year in matric I had the same teacher, Maths dipped to 50%.
My mother never had the money to put me into private maths classes, so I had to try and fend for myself, with no internet, and our entire school maths department a mess, I could not salvage my maths marks. Science I still got over 80% for, physics was my strong suite. The science teacher was decent enough to teach us the basics however.
This maths teacher used to go next door and ask the other maths teacher (Just as useless) the answer to any question that was asked in class. She did not understand it herself, so could not explain correctly, meaning she misslead the entire class. In a school where the pass rate was 99% that year, only 15% passed maths in matric. The other 85% that took maths failed on higher grade, some had to be dropped to standard grade to pass (Which supposedly adds 10% to your mark). So failing by less than 10% on HG could salvage a pass on SG.
You cannot say that all of that is attributed to bad students, being lazy. When they passed the rest of their subjects with distinctions. The stats point towards the majority of the blame being on the maths teaching department, not the students.