You are right about it seeming silly that you should have to learn all this maths that you are not going to teach but there is a workaround. While you are still an undergraduate in mathematics you can get teaching practice teaching mathematics. If it turns out the degree overwhelms you with mathematics don't worry, I've been there. Do a distance learning course in mathematics with the OU if you drop out of your brick uni and move to an easier module. If that still doesn't work out, change degree course and then do a pgce. That way you get more options about what you want to teach if you don't just want to teach mathematics. Or do a bachelor in education, if you want to teach in a primary school. Or a level 5 diploma in education and training, teaching mathematics; if mathematics is the only thing you want to teach. There is no need at all to be put off doing a maths degree when wanting to teach mathematics, when there is a will there is a way. You may even find the maths degree OK with hard work and get onto a pgce in mathematics, if you want to get into more senior, consultant roles in mathematics education.