In my classroom, the Desmos® calculator has been a game-changer for student understanding of relationships between graphs and algebraic representations of functions. We use this beautifully designed website every day. Lately, the Desmos class activity site (https://teacher.demos.com) and the new Activity Builder tool have proven especially useful by allowing me to provide my students with opportunities to struggle productively, create, error-check, and think deeply to learn mathematics. Activity Builder is the easiest tool I have found to set up and to run an activity that promotes these ideas in your classroom.
Edited by Robert Lochel Technology Tips offers a forum for innovative uses of technology in the teaching and learning of mathematics; it appears in every issue of Mathematics Teacher. Manuscripts for the department should be submitted via http://mt.msubmit.net. For more information, visit http://www.nctm.org/mtcalls.