sir i want to ask u that i have just given my math exam and i hope that i will get 98 m out of 100 my math is good but my science is not scoring 90 plus what i have to do after giving 10th exam guide me

see, u just need to be good at concepts and then u have to be far good in applying those concepts. Thats what IIT JEE demands. u are in 10th, u have 2 years for the IIT entrance (whether its name wud be JEE or ISEET). U can understand a lot of the three subjects (PCM). 

So, my advice is start from level zero of every chapter or topic. dont take pressure from now. u have lot of time for practise so dont directly jump to questions or exercises, first understand each and every concept. for this, u shud have a seperate notes copy of ur own (apart from ur schools or coachings notes). Study every chapter , makes notes of it then goto exercises part.