i get full confidence when i am writting the test but when the papers come i get less marks why?

Dear student,
We would suggest you that if you are facing such problems, follow the below pointers:
1) While studying do not cram the subject, try writing down every answer you learn.
2) While writing an exam, be stress free and careful,avoid careless mistakes.
3) When you complete your exam paper, revise it thoroughly before submitting it.

Thanks