Excel worksheets and workbooks are commonly considered number crunching tools. The primary focus is getting data into a worksheet, performing a few calculations, and arriving at an answer as quickly as possible. However, this prevalent mindset ignores many of the real goals and needed controls over worksheets that make them valuable decision-making tools. This course will examine worksheet and workbook best practices for layout and design, including segregating data, assumption, and calculations as well as documenting data sources and key calculations using comments. The materials will also cover important worksheet audit and other tools that ensure accuracy such as data validation, error checking, and inputting passwords to protect cells, worksheets and workbooks. Step-by-step instruction with screenshots and an Excel practice file are provided to enhance the learning experience.