This document outlines the key functions and operations of teachers. It discusses three main functions of teachers: diagnostic, prescriptive, and evaluative. The diagnostic function involves assessing students' entering behaviors and needs. The prescriptive function includes selecting appropriate content and teaching methods. The evaluative function is assessing student progress and outcomes. The teaching process involves three main stages: pre-active (planning), interactive (instruction), and post-active (evaluation). Key operations of teaching include planning lessons, organizing resources, implementing strategies, and controlling the system through evaluation and modification. Overall, the document provides an overview of the roles and processes involved in effective teaching.