Part of why this process may seem foreign in math (and what may scare a fair number of teachers of mathematics from the process) can be summed up in an entirely reasonable question: What if students get it wrong? As Thomas (2003) explains, the process is not about simply get- ting “correct” groups. Instead, Thomas recommends basing the lesson on discussion and comparison. Students should share their groups and then work with their classmates and teacher to compare and contrast their groups and the thinking behind their groups. Then, as the unit pro- gresses, students will revise their groups and their generalizations so that they are “actively engaged in constructing the big picture” (Thomas, 2003, p. 127).