Im sorry but you guys have short exams ;-; at my school they take 3 hours per exam (1 - 2 exams per day)
I also have 3 hours of maths 1 day (we have periods of 1 hour though, so mine is 3 periods unlike your 4 periods, but our teacher never just does basic maths for one day, we usually do revision, revision + game, then we use a website called MyMaths