Can somebody (human resource manager) help me understand how salary is prorated in malaysia ? Is there a standard way of prorating ?

Let us say an employee works 5 days week. But he works only 12 working days excluding saturday and sunday. What number do we divide by ?

x/y * basic salary.

Is y the number of days (max 31) in the month or number of working days in the month ?

Does x count as a working day to receive salary even for 5 days week employees?