Sherri Martinie is an associate professor of curriculum and instruction at Kansas State University, where she teaches undergraduate and graduate courses in mathematics education. Prior to taking her position at Kansas State, she taught elementary, middle, and high school mathematics for a combined 20 years. Sherri is an author, professional development leader, grant writer, and conference speaker.

 Jennifer M. Bay-Williams is a professor of mathematics education at the University of Louisville, where she teaches preservice teachers, emerging elementary mathematics specialists, and doctoral students in mathematics education. She has authored numerous books as well as many journal articles, many of which focus on procedural fluency (and other aspects of effective mathematics teaching and learning).

Sherri and Jennifer are co-authors on the Figuring Out Fluency in Mathematics series. You can find many  more games, routines, centers, and worked examples like these in the series newest classroom companions: Figuring Out Fluency: Addition and Subtraction with Fractions and Decimals and Figuring Out Fluency: Multiplication and Division with Fractions and Decimals.