Hiiii Sayanti!!!! To improve your spoken English, you need to impose engliEn in every aspect of your life. Try to talk to yourself in English. Also you can talk to your friends or anyone in English. When you learn new words or vocabulary, try to put that word in your sentence that you speak. Watch English shows, movies, etc. But always use correct grammar. Even when you are thinking something try to think in English. Try forming different forms of sentences. This will surely eventually develop your speaking skills 

For maths all you need to do is practise a lot. When you solve a chapter try to solve it from different books so that you get a vast variety of questions of the topic. Practice is the key to maths.