Fibonacci Sequence

The Fibonacci Sequence, developed by Leonardo Pisano in the 12th century, is commonly used in Agile methodologies for task estimation, particularly in Scrum. This sequence begins with 0, 1, and each subsequent number is the sum of the two preceding ones. For Agile estimation, a modified version is often used which includes numbers such as 0, 1, 2, 3, 5, 8, 13, and typically ends at 20, though it can sometimes extend to 40 and 100 to accommodate larger tasks.

In Agile practices, especially in Scrum, this sequence helps in estimating the relative size of tasks based on complexity and effort, not exact time. The choice of the Fibonacci sequence reflects its exponential nature, aligning with how complexity and uncertainty increase with task size. 

This approach not only aids in maintaining the flexibility of the development process but also plays a crucial role in uncovering different views, knowledge, and risks among the team members, fostering a deeper understanding and better outcomes.