Unit 1 summarized the history and rationale of Mathematics: K–8 Learning Progressions and discussed how aspects of the CCSS for Mathematics impact instruction.

The CCSS for Mathematics:

- Stress conceptual understanding, procedural skill and fluency, and problem solving
- Reflect a high cognitive demand for reasoning, sense making, and justifying
- Indicate that content and skills be connected to the CCSS Math Practices

The CCSS for Mathematics are organized by:

- Domains
- Clusters
- Standards

**Focus** (within grade level):

- Identifies essential skills and understanding students need to make sense of mathematics and know when and how to use the skills they learn
- Identifies key ideas, understandings, and skills for each grade or course and stresses deep learning, applying concepts and skills within the same grade or course

**Coherence** (across grade levels):

- Reflects the ways in which students build on and connect skills and concepts in order to develop deep understanding
- Articulates a progression of topics across grade levels
- Connects ideas with other ideas enabling students to learn with understanding, develop skill proficiency, and solve problems

According to the **Institute for Mathematics in Education** at the University of Arizona, the CCSS for Mathematics:

- Were built on progressions — narrative documents describing the progression of a topic across a number of grade levels
- Are informed by research on children's cognitive development and by the logical structure of mathematics

According to the **National Research Council,** mathematics progressions:

- Are the path that students might follow as instruction helps them move from naïve ideas to more sophisticated understanding
- Are descriptions of successively more sophisticated ways of thinking about an idea that follow one another as students learn
- Are not inevitable and do not have one correct order