Hello,

Grace marks are given for the candidates who have failed by just one 1 or 2 marks or who haven't met the qualifying criteria. This year CBSE class 12th and 10th board examinations were cancelled and the results for class 10th will be on basis of performance in internal assessments, the evaluation will be unbiased and fair. 89% is a decent score and it might not be rounded off to 90% because the performance in the internal exams will be taken in to consideration. CBSE on May 1, 2021 released a policy notification for evaluation of class 10th results and the each and every CBSE school shall adhere to the guidelines and evaluate the results. You will find the policy notification released by CBSE through the link given below

https://www.cbse.gov.in/cbsenew/documents/POLICY%20NOTIFICATION.pdf