AddDays adds the specified number of days to the date.

AddMonths adds the specified number of months to the date.

AddYears adds the specified number of years to the date.

DaysBetween calculates the difference in days between two dates.

DaysInMonth returns the number of days in the specified month of the specified year.

FormatDate formats the date to "YYYY-MM-DD" by default, or uses a custom layout if provided.

IsWeekend checks if the given date is a Saturday or Sunday.

ParseDate parses a date string with a specified layout, or "YYYY-MM-DD" by default.