Desc: How Did Romans Count to 100?: Directed by Andy T. Jones. Have you ever wondered how people counted to 100 before modern numbers were invented? A basic explanation of Roman numerals, examples of how they are used today, and step-by-step instructions on how to use them are explored in this newest addition to the How Do series. The How Do series is a great introduction to various STEM topics, each presented in a format that encourages audiences to ask questions and guess the answers before exploring the science behind them.