Common Core State Standards are a set of standards, not a curriculum.
The Common Core State Standards are a common set of educational standards defining the mathematics and English language arts knowledge and skills all United States students in grades K-12 need to be successfully prepared for college and the workforce in the 21st century.
The standards are not a step-by-step guide for classroom instruction; rather, they are an outline of the goals to be reached and skills to be mastered at every grade level and upon graduation. It is important to understand what educators mean when they use the word standards. Standards are the end goals for students. They are a list of skills and facts students need to acquire throughout the course of the school year.
The Common Core provides an expected destination, and schools and teachers are free to chart their own course to that destination. This is the important distinction between standards and curriculum. If you imagine standards as a destination, the curriculum is the map to get there. A curriculum outlines the sequence of topics that teachers will cover on their way to the final goal of the standards, building from simpler tasks to more difficult and complex ones.
For example, one of the Common Core math standards for eighth grade expects that at the end of that grade, a student should be able to:
“Construct a function to model a linear relationship between two quantities. Determine the rate of change and initial value of the function from a description of a relationship or from two (x, y) values, including reading these from a table or from a graph. Interpret the rate of change and initial value of a linear function in terms of the situation it models, and in terms of its graph or a table of values.”In this example, teachers could have students model the relationship between any two variables (rainfall and wheat growth, age and height, inflation and GDP) and students would simply need to fit an equation to the data. Teachers could similarly build toward this end goal in any way they like, perhaps starting with the Cartesian coordinate plan and moving to reading tables and graphs, or vice versa, or even by an entirely different approach.
In short, the Common Core provides a destination, and schools and teachers are free to chart their own course there.