In this article about the Common Core State Standards and mathematics, the author wanted to point out what's familiar in these standards and to give teachers clear access to what's different about them. She wanted to emphasize what has made her passionate about the Common Core standards--which is their two-part structure: Standards for Mathematical Practice and Standards for Mathematical Content, both equally important. The Standards for Mathematical Practice include the same eight standards for all grades. These practice standards describe the "expertise that mathematics educators at all levels should seek to develop in their students"--that is, the ways they want students to engage with the mathematics they're learning. In contrast, the Standards for Mathematical Content include many more standards, which are different for each grade. These content standards "define what students should understand and be able to do." They are organized into domains, each of which includes clusters of related standards so as to present mathematics as a subject of closely related, connected ideas. Teaching to the Common Core standards calls for making both the practice standards and the content standards integral to classroom instruction. The challenge of the Common Core standards is to help all students develop enough mathematical expertise to be prepared for college or the workplace--and successful futures. (Contains 2 endnotes.)