This paper supports grades 3-5 mathematics teachers and considers how technology in the classroom can be used to support "low threshold, high ceiling" tasks and productive discussion. We present a description of a card-sorting task to support the "5 Practices of Productive Mathematics Discussions" focused on an online task designed to: be open to multiple levels of strategies, reveal misconceptions, and support students in developing more sophisticated conceptual understandings of area measurement. We present a sampling of strategies created by teachers (who were pretending to be elementary students) in past activities. We discuss approaches to connecting strategies for deeper understanding of area measurement.