# Design Principles

### Developing Conceptual Understanding and Procedural Fluency

Each unit begins with a pre-assessment that helps teachers gauge what students know about both prerequisite and upcoming concepts and skills, so that teachers can gauge where students are and make adjustments accordingly. The initial lesson in a unit is designed to activate prior knowledge and provide an easy entry to point to new concepts, so that students at different levels of both mathematical and English language proficiency can engage productively in the work. As the unit progresses, students are systematically introduced to representations, contexts, concepts, language and notation. As their learning progresses, they make connections between different representations and strategies, consolidating their conceptual understanding, and see and understand more efficient methods of solving problems, supporting the shift towards procedural fluency. The distributed practice problems give students ongoing practice, which also supports developing procedural proficiency.

### Applying Mathematics

Students have opportunities to make connections to real-world contexts throughout the materials. Frequently, carefully-chosen anchor contexts are used to motivate new mathematical concepts, and students have many opportunities to make connections between contexts and the concepts they are learning. Additionally, most units include a real-world application lesson at the end. In some cases, students spend more time developing mathematical concepts before tackling more complex application problems, and the focus is on mathematical contexts. The first unit on geometry is an example of this.

### The Five Practices

Selected activities are structured using Five Practices for Orchestrating Productive Mathematical Discussions (Smith & Stein, 2011), also described in Principles to Actions: Ensuring Mathematical Success for All (NCTM, 2014), and Intentional Talk: How to Structure and Lead Productive Mathematical Discussions (Kazemi & Hintz, 2014). These activities include a presentation of a task or problem (may be print or other media) where student approaches are anticipated ahead of time. Students first engage in independent think-time followed by partner or small-group work on the problem. The teacher circulates as students are working and notes groups using different approaches. Groups or individuals are selected in a specific, recommended sequence to share their approach with the class, and finally the teacher leads a whole-class discussion to make connections and highlight important ideas.

### Task Purposes

- Provide experience with a new context.

Activities that give all students experience with a new context ensure that students are ready to make sense of the concrete before encountering the abstract. For example, as their first encounter with a constant speed context in grade 6, students move a pre-measured distance at a constant speed and time each other (or watch a demonstration of this).

- Introduce a new concept and associated language.

Activities that introduce a new concept and associated language build on what students already know and ask them to notice or put words to something new. For example, in grade 8, students use a picture of a figure and the same figure transformed to describe the move as, for example, a “quarter turn.” Over the course of later activities, they formalize the idea of a rotation about a point by a specific angle.

- Introduce a new representation.

Activities that introduce a new representation often present the new representation of a familiar idea first and ask students to interpret it. Where appropriate, new representations are connected to familiar representations (as in tables of equivalent ratios and double number line diagrams) or extended from familiar representations (as in extending the number line to the left to show negative numbers in grade 6). Students are then given clear instructions on how to create such a representation as a tool for understanding or for solving problems. For subsequent activities and lessons, students are given opportunities to practice using these representations and to choose which representation to use for a particular problem.

- Formalize a definition of a term for an idea previously encountered informally.

Activities that formalize a definition take a concept that students have already encountered through examples, and give it a more general definition. For example, the term $\pi$ is not defined until the end of the third lesson about measuring circles in grade 7.

- Identify and resolve common mistakes and misconceptions that people make.

Activities that give students a chance to identify and resolve common mistakes and misconceptions usually present some incorrect work and ask students to identify it as such and explain what is incorrect about it. Students deepen their understanding of key mathematical concepts as they analyze and critique the reasoning of others..

- Practice using mathematical language.

Activities that provide an opportunity to practice using mathematical language are focused on that as the primary goal rather than having a primarily mathematical learning goal. They are intended to give students a reason to use mathematical language to communicate. These frequently use the Info Gap instructional routine.

- Work toward mastery of a concept or procedure.

Activities where students work toward mastery are included for topics where experience shows students often need some additional time to work with the ideas. These activities are marked as optional because no new mathematics is covered, so if a teacher were to skip them, no new topics would be missed.

- Provide an opportunity to apply mathematics to a modeling or other application problem.

Activities that provide an opportunity to apply mathematics to a modeling or other application problem are most often found toward the end of a unit. Their purpose is to give students experience using mathematics to reason about a problem or situation that one might encounter naturally outside of a mathematics classroom.

*A note about standards alignments: *There are three kinds of alignments to standards in these materials: building on, addressing, and building towards. Oftentimes a particular standard requires weeks, months, or years to achieve, in many cases building on work in prior grade-levels. When an activity reflects the work of prior grades but is being used to bridge to a grade-level standard, alignments are indicated as “building on.” When an activity is laying the foundation for a grade-level standard but has not yet reached the level of the standard, the alignment is indicated as “building towards.” When a task is focused on the grade-level work, the alignment is indicated as “addressing.”