Schools often struggle with how to teach mathematics in a way that engages children and prepares them for high school and college course work. One of my favorite books on the subject is A Mathematician's Lament by Paul Lockhart, subtitled How Schools Cheat Us Out of Our Most Fascinating Art Form. Aware of the ongoing tension between teaching conceptual mathematics and computational skill practice, I have written about some of the wonderful ways CDS teachers make math real for students, from preschoolers using multi-colored teddy bear shaped counters to develop number sense, to eighth graders estimating angles and the length of line needed as they drop Barbie and Ken dolls on bungee cords off of the third floor balcony. Yes, we need to rethink the way we teach math in elementary schools. Realistically, that depends on high schools rethinking what they are teaching and how they expect students to be prepared. This is a case where top down reform is needed, beginning with the colleges. For inspiration, check out this New York Times article, "How to Fix Our Math Education." I’ve also included three videos below that demonstrate how CDS third graders learn subtraction through strategies such as a number line, regrouping and the standard algorithm.