Reply To: Lesson 4-2: Where Comparison Lives In Additive Thinking – Discussion

[Christina Michaels]

I think my students– struggling middle schoolers– would jump right in to an algorithm. I think adding and subtracting is something they view as a strength of theirs, and where they comfortably live. The problem (like the 1001-999 example in the video) is that if students make mistakes in the algorithm, they often don’t recognize that they’ve made mistakes. I think using number lines is a powerful way to help build that number sense– how far apart are these numbers? does your answer make sense?