I was greatly inspired by the Finnish group of mathematicians which hacked out an open math textbook in 3 days, by Siyavula's content sprints, and by Boundless's recent physics book hackathon.
So, when some unexpected funds came along, I suggested we hack out an open arithmetic/prealgebra book over a weekend. I solicited help from faculty involved in the Washington Rethinking Precollege Math project, who I consider to be thought leaders on lesson study, faculty inquiry, persistence, and innovative instructional strategies. I also called up my friends and colleagues down in the Maricopa college district, who I consider to be leaders in the move to bring open education resources (OER) into the classroom, especially at the developmental level. They also have been doing a mass re-visioning of the dev math curriculum, based on the CCSS and carefully researched learning trajectories.
After a couple online planning meetings, it became clear that the group was not interested in writing a traditional textbook. Partly, this was recognition that the books largely serve as instructor guide nowadays, and most student's only use the book narrative as an occasional reference, turning to in-class lecture or online videos when they get confused. So, we planned instead to attempt to create a set of resources covering the spectrum of what an instructor and student would need to teach and learn arithmetic: Topic intros, contextual motivations, concept development, guided practice, interactive reference (like videos and animations), static references (written examples), practice problems, and wrap-up activities.
We wanted to both create materials that students would directly consume, but also create materials for the instructor. For example, it is good practice to use manipulatives to develop conceptual understanding, and to show alternatives to the standard algorithms for doing calculations, but not all instructors know how to do these things. Rather than write a text that explains it, we figured videos for the instructor might be more useful. Some of these could either serve the instructor or the student.
So from Dec 18 - 20, 2012, a group of 4 faculty from Washington, myself included, traveled down to Arizona and worked with a team of faculty from across the Maricopa district. Predictably, you get a group of very excited and passionate teachers in a room together, and quickly the "work session" turned into a very valuable sharing and exchange session.
But, in addition to the new ideas and inspiration we got from our colleagues, we were able to produce a number of exciting products. You can find our official collection here, but a lot of people are still working on items, or have large collections of items that didn't make sense to add this this listing site (notably, Scottsdale's workbook), and many of the other items from their SCORE site.
So while we didn't manage to write a book in 3 days, I'm very excited about the foundation we laid towards building quality and innovative open resources for arithmetic and prealgebra.