Hi Abika,

JEE Main Exam is of total 300 marks and total 90 questions are there. Out of 90, you are required to answer 75 questions only. Each subject will have 20 MCQs and 10 numerical ques out of which 5 is must. If we talk of marking scheme than,

• MCQs - 4 Marks will be awarded for every correct answer and 1 Mark will be deducted for every incorrect answer
• Numerical - 4 Marks will be awarded for every correct answer and 0 Mark will be deducted for every incorrect answer

Refer here for more info - JEE Main Exam Pattern 2021 (New)- Exam Mode, Duration, Marking Scheme (careers360.com)

Feel free to ask doubts in the Comment Section.

I hope this information helps you.

Good Luck!