Intro to EMA and Parsing

This activity is a multi-lesson re-engagement around order of operations and structure of expressions, intended for 9th graders who have not learned it successfully prior to high school. The idea of starting with a commutativity mini-exploration and emphasizing the use of area models was influenced by Jemma Sherwood. In the past, I've focused only on the repeated addition / repeated multiplication aspect, but I think the area model provides a more solid foundation for understanding why multiplications come before additions. To that end, I also added in some material from this excellent FAL lesson: Representing the Laws of Arithmetic. Finally, I've used the concept of parsing to reveal terms and factors for several years now, and find that it really helps students see the structure of even the most complicated expressions. I first saw this idea in a really interesting thesis written by Ethan Merlin (if anyone knows Mr. Merlin, please let him know that his ideas have been put to good use!).

By Daniel Wekselgreene