Hi Allie,
To answer the question, why an ISTJ is suggested teaching maths over teaching another subject:
Keeping in mind that everyone is different, and certainly there are many exceptions of course. The test doesn't measure education, intelligence and environment, which play crutial roles in who we are, and what we want. However, to explain in terms of type:
I in the INTJ. Introverted teachers better in sciences as they need less expressive explanations than say humanities, arts, drama.
T in INTJ. Thinking, rather than working with feeling (which often translates as strength in jobs and tasks involving human relationships). You are more likely to be better at teaching things which don't require more of the human touch, (like Physical eduction, music), but better again in things like maths, chemistry, physics.
Sensing. Sensing people like concrete ideas and facts, over hunches or feelings. So, again, maths. It is as concrete as you can get.
Finally, J. You are organised and structured. Hence would be better at teaching things that fall into this category.
If you were higher in P, then you could be better at teaching say marketing or business, which are subjects which have maths elements, but you need to have strengths in being reactive and at times creative. Things which are inline with the Perceiver rather than the Judger.
So, generally, ISTJ is more suited to teaching maths, but doesn't mean necessarily that you are, or that you want to me.
Hope this explanation is satisfactory.
Regards,
Vern
www.career-test.co.uk