Question: Why was the work with percents taken out of the 5th grade curriculum in the 3rd edition?

Answer: In the 1st and 2nd editions of Investigations, there was a unit (Name that Portion and What’s That Portion?) that included lessons that connected what 5th graders already knew about percents to what they already knew about fractions and decimals. These concepts were taught together, rather than separately, and built strong conceptual understandings of the meaning of percents and their relationship to fractions and decimals.

As a math coach, I remember doing professional development with teachers and visiting classrooms and being amazed at the math being learned. I think many of us learned that the only way to find what percent equaled 5/6 was to divide 5 by 6, carry out the long division, and then multiply by 100 to get the answer. Instead, what I saw teachers doing in our professional development sessions, and students doing in their classrooms, was using what they knew about fractions and about fraction and percent equivalents to answer this question. They would decompose 5/6 into 1/2 and 1/3, and then because they “just knew” that 1/2 = 50% and 1/3 = 33 1/3%, they knew 5/6 = 83 1/3%. It was brilliant!

As we began working on the 3rd edition, there were two major influences on our work. One related to what we were learning from teachers using the curriculum and their students. One thing we were often seeing was students over-relying on fraction percent equivalents to answer questions about comparing fractions, or to add or subtract fractions. Rather than making sense of the problem, and using what they knew and understood about fractions as numbers, or what they knew about the operations, students were using percent equivalents in ways that made little sense. The other major influence was the content standards of the Common Core State Standards (CCSS), where learning about percents didn’t begin until grade 6. We knew if we included this work with percents, there were going to be significant issues with alignment to the CCSS.

This became a very complicated discussion. We had to consider the total number of sessions in the entire year. We had to consider the CCSS and the new content (e.g. multiplying and dividing with rational numbers) we needed to add. And, based on what we’d learned from the field, we had to decide what to do about these percent lessons. After many long discussions, we decided that we could not go “halfway” with this work on percents. If we wanted to use that content, it would add even more lessons to the year-long curriculum. Given all of these factors, we made the extremely difficult decision to remove this work from the 3rd edition. I’m not sure there was any decision we made in Grades 3-5 that was harder for me than this one.