Clip 7/17: Day 14: Subtracting from inside the original quantity

Understanding and Reading Problems: Once they’ve all engaged with the problem in relevant and authentic ways, Mia can then challenge pairs to defend their thinking and uncover student misconceptions.  She knows that students are likely not yet to understand that in a subtraction problem, there is a quantity being removed from another.  She asks her students, “Where are the ones coming from?” and follows their responses.