“…New theories of mathematical cognition (Bransford, Brown & Cocking, 1999;Brown & Campione, 1994;Greeno & Goldman, 1998;Hall & Stevens, 1995;Lakatos, 1976;Lemke, 1993;Livingston, 1999) and math education (Boaler, 2008;Cobb, Yackel & McClain, 2000;Lockhart, 2009;Moss & Beatty, 2006), in particular, stress collaborative knowledge building (Bereiter, 2002;Scardamalia & Bereiter, 1996;Schwarz, 1997), problem-based learning (Barrows, 1994;Koschmann, Glenn & Conlee, 1997), dialogicality (Wegerif, 2007), argumentation (Andriessen, Baker & Suthers, 2003), accountable talk (Michaels, O'Connor & Resnick, 2008), group cognition (Stahl, 2006) and engagement in math discourse (Sfard, 2008;Stahl, 2008a). These approaches place the focus on problem solving, problem posing, exploration of alternative strategies, inter-animation of perspectives, verbal articulation, argumentation, deductive reasoning and heuristics as features of significant math discourse (Maher, Powell & Uptegrove, 2010;Powell, Francisco & Maher, 2003;Powell & López, 1989).…”