Kindly tell me how the overall grade is computed from each FA and SA? Just by adding gradepoints or by adding marks and converting to grades

My Grades are as follows

Subject FA1 FA2 SA1 Term-1 (FA+SA)

English B1 A2 B1 (69.5/90) B1
Hindi A2 B1 B2 (55/90) B2
Maths A1 A1 A2 (74/90) A2
Science A2 B1 A2 (73.5/90) B1
Social A2 A1 A2 (76/90) A2

Can you tell me how overall grade is obtained in each subject