Math is such a subject that if you make a small mistake then your marks will be deducted. What you do that when you attempt a problem check it again. Sometime in the procedure you miss something .
i think you are a bit care less . When you finish paper, always make a habit to read it again . If you have time, the other thing you do ,
Try to attempt a paper while sitting home & then give marks yourself like an examiner. then you will rectify your mistakes. i myself learn in this way .
Try & then tell me .