When people say "average", they almost always mean the arithmetic mean — sum every value, then divide by how many values there are. In academics this is how an unweighted percentage is computed across subjects when every subject is out of the same maximum.
Formula:
Mean = (Value₁ + Value₂ + … + Valueₙ) / n
The mean has well-known weaknesses. It is sensitive to outliers — one student scoring 5% drags the class mean down disproportionately. For class-performance analytics, the median (middle value) is often a better summary than the mean because it ignores extremes.
For board-result computations, "average" almost always means the arithmetic mean of the five main subjects, then converted to percentage with the same formula as percentage of marks: (Sum of obtained / Sum of maximums) × 100.
There are three other "averages" worth knowing: • Median — the middle value when sorted. • Mode — the most frequent value. • Weighted mean — covered in the Weighted Average glossary entry.