Developed through an NSF-funded grant, this website offers several features that teachers might find useful. There are "Poster Problems" (Grades 6-7 currently) which are two-day lessons that focus on exploration of interesting situations (e.g. "The Intensity of Chocolate Milk") and follow a general Launch-Explore-Summarize format, focusing on student reasoning and discussion. Also, AlgebraByExample focuses students on "worked examples that students are prompted to analyze and explain." This is an excellent resource for teachers looking to use student work in the classroom.
101 Questions
This website provides interesting photos and videos that can be used to teach students how to ask questions about situations. These questions can be mathematical or not, but the randomized images foster curiosity in students if implemented properly.
This site has, in addition to videos of quality teaching addressing the Math Practices, sets of tasks that are ideal for implementing in the classroom. Recently, the site as added a set of performance tasks (some of which are found in the resource below this one). These tasks foster student understanding as well as offering excellent opportunities for dialogue and classroom discourse.
Part of the Mathematics Assessment Project, these tasks are designed as contextual situations (some real-world, some mathematical) that can be used in classrooms. There are three levels to the tasks: novice, apprentice, and expert. The tasks are for middle school and high school students. Also, there is a collection of formative assessment lessons, based on these and other tasks and designed to engage and re-engage students with material in a formative manner.
This one will take some time to sort through, but Dan Meyer has collected all of his "3-Act Tasks" into a spreadsheet and aligned them to content and practice standards from the CCSSM. A link to Dan's blog article on using 3-Act Tasks during instruction is the second link. These tasks are a great way to introduce different stimuli, technology, and inquiry into your classroom.
The Georgia Department of Education has developed a set of units with associated games, performance tasks, and performance assessments. Many of these activities are of high quality and are classified into levels of learning. They are a useful resource when searching for quality hands on activities to add to your curriculum.
Illuminations is a collection of tasks and lesson plans written by teachers all over the country and archived by the National Council of Teachers of Mathematics (NCTM). The database is searchable and filters by CCSSM Domain and by standard.
SEM is a set of more involved tasks that are better suited to investigation by students as opposed to individual work. The explorations are released periodically and include such topics as "7 Billion . . . and Growing" (released May 2015), which is a problem centered on world population. During most problems, students engage with multiple areas of mathematics and learn to think critically.
This is a free set of PDF textbooks for an integrated Secondary curriculum. The materials are problem-based, with a decent balance of procedural practice. The materials were created by a group of teachers in partnership with the Utah Department of Education. Course titles include Secondary Mathematics 1, 2, and 3 as well as Honors Secondary Mathematics 1, 2, and 3.
Beginning as a Michigan Mathematics and Science Partnership grant (and similar to Algebra 4 All, below), the EMATHS project contains units of study as well as a collection of tasks for each course in the high school sequence through Algebra 2. These tasks are complex, contextualized, and engage students with multiple representations of mathematical entities.
Although this is the main interface for the "social network" aspect of the Algebra 4 All project, it also has a large number of tasks under the "Resources" tab. This project originated in Michigan as a Mathematics and Science Partnership Grant. The program ran for several years (along with Project PRIME) using a large number of resources generated for use with teachers in professional development. These resources are meant to be used in classrooms with students and involve context-based problems that engage students with multiple representations and center on important concepts in Algebra.
This site has some great examples of problems and tasks aligned to individual standards in the CCSS-M. It's very helpful in clarifying the meaning of some standards that have murky or ambiguous language.
This site is a great synthesis of the Kansas flipbooks and much more. The resources are aligned by standard and separated into instruction and assessment categories. Van de Walle's work is heavily referenced throughout the materials, problems, and examples. While there is a lot of information on this site, it is a great resource for teachers looking to learn more about instruction under the CCSS-M.
NOTE: to access other grade levels, simply look to the right side of the Grade 4 wiki, about half way down the main page.
The Math Forum at Drexel University is a great site that has many resources and in particular problems and tasks that can challenge students at all levels. Problems of the Week are available at all levels and specifically get at the Standards for Mathematical Practice. The library of these problems is searchable by grade, domain, or math practice.