Math teaching

Yes teaching at uni may be possible but without a PhD means that you may loose out to pple who has one when it comes to employment. I suggest you to start from junior positions such as tutor to gain some experience in teaching then go for higher positions at later stage such as Lecturer (or Assistant Professor if it is US system). Even without a PhD, your teaching experience and reputation within the dept will give you advantage over fresh grad PhD students.

I assume you got at least an MSc right? Cos otherwise teaching in uni is far too ambitious.

If you just wanna settle as a high school teacher, then a degree + a teaching certificate will be adequate.

Hope this helps :)

I think it's not possible because teaching high college or university's level maths requires clear mathematical logic and sense. So, PHD in Mathematics is a must if you would like to teach Maths in local universities. As for the case in college, a bachelor degree of maths and a teaching certificate are enough for teaching college level's mathematic.