I need help adding cardinality to a ER diagram

Assumptions:

• A project can exist before anyone is assigned to it
• An employee may not be assigned to any projects.
• An employee may not be assigned to more than 3 projects.
• An employee is assigned to only one department and must be assigned to a department.
• If an employee is assigned to a project, they must be assigned to at least one task but no more than 4 tasks.
• A department could exist and not have any employees.
• A project must have at least one task and a task could not exist unless there was at least one appropriate project.

(My diagrams maybe off)

Emp num Project pn() phame Project Task ono ploc tno tno duration ebdate Department dno Task dno tno pno t duration Project Employee Has Have Emp-num Project_Task Has Department Task