The learning curve is one of the tools in operation planning and control. It enables the planner to estimate future performance of tasks executed either by individuals or organizations. In fact, every task is composed of elements, or subtasks. Therefore, the learning curve of the task is derived from the learning curves of the component elements and their frequency within the task. The paper discusses the nature of the aggregated learning curve as well as ways to calculate the values of its parameters. The nature of the aggregated learning curve is found to be different from its components (that is, the value of its parameters and its equation are not the same).