What is the fourth subject and how does it affect GPA?

The fourth subject is an extra, optional subject taken alongside the compulsory ones. Its defining feature is that it does not count towards GPA the way the others do: the minimum points needed to pass are subtracted from its grade point, and only what remains is added to your GPA.

That is why doing well in the fourth subject raises your GPA while doing badly does not lower it — in the worst case it contributes nothing. The risk is one-sided by design, so that a student can take an extra subject without fear.

It would still be a mistake to treat it casually. Being absent from it or filling the form wrongly can complicate your result, and some university departments require that you studied a particular subject — which for many students is the one they took as their fourth.

Which grade carries which point value, and what the pass point is, are set out in the board’s published grading structure. Those numbers are deliberately not printed here — reading them off your own board’s published grading table is the reliable route.