Marks of all subjects will appear in the marksheet. If someone has failed or scored less in one subject and passed in remains subjects including the additional subject, the mark of additional subject will replace the subject. The person will pass grade 10 but will he or she have to appear for reexamination of subject in which he or she has failed.

A 6th subject can help you improve your overall percentage, especially if you opt for an easier and higher-scoring subject. In case you score higher in your 6th subject, the marks obtained in it will substitute your 5th subject in your percentage calculation. Thus, your overall percentage will increase.

As per CBSE guidelines:

• A language offered as an additional subject may replace a language in the event of a candidate failing in the same, provided after replacement the candidate has English/Hindi as one of the languages.
• An elective subject offered as an additional subject may replace one of the elective subjects offered by the candidate.
• It may also replace a language provided after replacement the candidate has English/Hindi as one of the languages.
• Additional language offered at the elective level may replace an elective subject provided after replacement the number of languages offered shall not exceed two.