I am appearing boards 12. and I have putted wrongly the number of answer would it deduct the marks.

Not at all, you do not need to do any work. There is no negative marking in boards examination, so you do not need to worry about this and just focus on your next paper now all the best Is about putting the wrong number of answer it could happen so don't worry no marks will get deducted.

If you have given wrong answer for MCQ type or descriptive type questions, then no marks will be given for wrong answer and also there will no negative marking for any wrong answer. Hence no marks will be deducted for any wrong answer.