Hello Aspirant ,

This is a common problem among students who are relatively weak in Mathematics and there is only one solution to this problem and that is that you practice so many questions of a single topic and keep revising them after a certain period of time , it will take some time to getting used to it but you will be much better at mathematics after doing this .

Another thing you can do is make your own notes after understanding a topic and again keep revising it .

Hope this helps.