“…In the context of ACAT, educational technology, such as mathematics apps, are artifacts, mediating the activity between the child (i.e., subject) and the mathematics (i.e., object). However, few mathematics apps are effective in supporting students' development of mathematics knowledge [8], as the vast majority of apps involve little more than passive, repetitive practice [7]. However, some apps feature virtual manipulatives, which are "an interactive, technology-enabled visual representation of a dynamic mathematical object, including all of the programmable features that allow it to be manipulated, which presents opportunities for constructing mathematical knowledge" [23] (p. 13).…”