Before preparing for any exam one must be clear about their final aim. Since you have dilemma between two widely different fields, it becomes imperative that you choose either one of them first. If you wish to have a career in teaching at college level then NET is a suitable exam;but if you wish to become a civil servant then you will have to appear for Civil Services exam conducted by the UPSC. If your choice is NET then you need not worry about maths paper because paper 1 in this exam asks for general teaching aptitude based questions and paper 2 is subject-specific. You will not be required to give maths paper. However, in the Civil Services exam, paper 2 is aptitude based which is of qualifying nature (need to score minimum 33% of the allotted marks),but don't feel disheartened because the UPSC asks elementary level maths upto 10th standard only. Also, you can improve you’re your hold on the subject by brushing up the basics and by practising some model aptitude test papers to improve your weak areas in the subject.