There are many hoops through which one must jump before becoming a California teacher. The first is a bachelor's degree, and the second is passing the dreaded California Basic Educational Skills Test, or CBEST.
The CBEST has three parts: reading comprehension, essay writing (when I took it, my essay prompt was to write a letter to the editor of a newspaper), and math. The math is at most at the 7th grade level, which is even lower than that required for California's high school exit exam.
I know this sounds harsh, but anyone with a bachelor's degree who can't pass that test is an idiot. Yet there are plenty of people who don't pass it, and they get to take it over and over until they do. In fact, they only have to retake those portions of the test that they previously failed--yet they get the full 5 hours (or whatever) to retake only those portions.
If I had my way, I'd impose the following rule: fail any part of the CBEST, and you cannot retake it for one year--and then, you must retake the entire test. Again, allow me to be blunt: do you really want people who perform at a level lower than the high school exit exam potentially teaching students? Do you really want to justify why an English teacher with a bachelor's degree (someone who in theory, at least, passed Algebra 2) can't pass 7th grade math? Do you want a math teacher who can't string coherent sentences together, or who can't spell? Do you want these same people teaching elementary students?
If you truly value children and their education, you must come to the conclusion that my suggestion above isn't draconian at all. In fact, it should be a bare minimum.
Then you must marvel at the greed and cynicism that inspires a CBEST-prep workshop put on by the teachers union.