Read Methods, strategies, and elementary content for beating AEPA, FTCE, ICTS, MSAT, MTEL, MTTC, NMTA, NYSTCE, OSAT, PLACE, PRAXIS, TEXES for free! The content is applicable to CSET Multiple Subjects, too.
It looks like candidates can "borrow" a text that I co-authored for multiple subject exams here:
https://archive.org/details/methodsstrategie0000boos
Unfortunately, the editing on this text was sub-par, and you will find plenty of errors in it. My chapter on language arts is the only one that I can really vouch for. I do not recommend paying for this text - I would just read it online. It is out of print, so if someone wants to copy the text upload a .pdf to archive.org, I am fine with that.
Anyway, I paid someone to edit the math chapter, and the corrections are here:
https://www.scribd.com/doc/24502459/Math-Corrections-for-Chapters-14-19-v2
Regards,
Chris B.