What are the primary functions or activities of management?

Planning, organising, staffing, directing, and controlling

Management is defined as a process of getting things done with the aim of achieving goals effectively and efficiently. There are 3 elements in this definition-
(a) process
(b) effectively
(c) efficiently
Process in the definition means the primary functions or activities that management performs to get things done. These functions are planning, organising, staffing, directing and controlling.
Being effective or doing work effectively basically means finishing the given task. Effectiveness in management is concerned with doing the right task, completing activities and achieving goals. In other words, it is concerned with the end result.
Efficiency means doing the task correctly and with minimum cost. There is a kind of cost-benefit analysis involved and the relationship between inputs and outputs.