* School calendar: School calendars vary by district, state, and even country. Some have more days in a month than others due to different scheduling of breaks, holidays, and weekends.
* Number of school days in a week: Most schools operate on a Monday-Friday schedule, but some might have a different structure.
* The specific month: Even within the same school year, the number of school days can vary from month to month due to holidays and breaks.
To find the answer for a specific student, you would need to check their school's calendar for the month in question.