Oh speech on maths wow c according to the best advice is that if u r could in maths thn u can easily write an speech on maths. I could help u a little as me also not vry gud on maths but not vry bad tht could nt help u. Focus on formulas based sums especially if u good in trigonometry. As in higher class the teacher mainly see the trigonometry based formula thn focus on other chapters like hyperbola, parabola, straight line, circle. mentions is importance why this formula is required for this sum y not for tht sum. mention also who had invented thm and for wat purpose. 
i hope this much will be ok for u. best of luck.
thank u.