In this note we demonstrate two instances where matrix multiplication can be easily verified. In the first setting, the matrix product appears as matrix element concatenation, and in the second, the product coincides with matrix addition. General proofs for some results are provided with a more complete description for 2×2 matrices. Suggested for…

In this article we consider two triangles: one inscribed in another. We prove that the area of the central triangle is at least the harmonic mean of the areas of corner triangles. We give two proofs of this theorem. One is based on Rigby inequality and the other is based on the known algebraic inequality, to which we bring a new, geometric, proof.…

To explore and identify gaps in students' opportunities to take and prepare for advanced math since the coronavirus disease 2019 (COVID-19) pandemic, RAND Corporation researchers conducted a nationally representative survey of teachers and principals in spring 2022. The researchers focused on two key ingredients that enable equitable student…

The Klein bottle and hairy ball theorem are important concepts in advanced mathematics and they are both examples of the Poincaré-Hopf theorem. Complex theories such as these usually remain unrealized in the minds of mathematicians. In this collaborative work between a mathematician and a designer, we introduce the concept of the hairy Klein…

"Representational transformation diagrams" are used to compare and contrast standard textbook presentations of vector line integrals in undergraduate courses in both mathematics and physics. These presentations are taken as the lower anchor in a learning trajectory. Two principal approaches in the lower division are identified, roughly…

Math achievement plays a pivotal role in students' success in school and beyond. Algebra, in particular, serves as a crucial gateway: it increases the chances a student takes advanced math in high school, which has implications for their college and career prospects. In 2023 and 2024, the American Mathematics Educator Study (AMES) surveyed…

In this article, we use a simple lattice model to illustrate the concepts of entropy, free energy, and thermodynamic equilibrium from a microscopic perspective. These physical concepts are based on elementary knowledge of discrete probability distribution and weighted average. Calculations about this model involve basic algebra and counting, which…

Given math's importance, states are adopting a range of K12 policies to improve math outcomes. As these and other policies unfold, policymakers need to monitor intended outcomes and ultimately gauge impact. They need answers to basic questions: Are more students taking and passing algebra and advanced math? Are performance gaps changing between…

In this survey paper, we describe the state of the field on linear algebra research. We synthesize themes, questions, results, and perspectives emphasized in the papers that appear in this issue, as well as a selection of those published between 2008 and 2017. We highlight the extensive base of empirical research detailing how students reason…

Historically, what people can learn is co-determined by the "representational infrastructure" for knowledge building. When Latin was the required medium of knowledge building, few could engage in scholarly activities; without the change to the vernacular, nearly universal access to higher education would not be possible. The highly…

Advanced mathematics courses have been developed and refined by the first author, using an action research methodology, for more than a decade. These courses use the computer algebra system (CAS) Maple in an "immersion mode" where all presentations and student work are done using Maple. Assignments and examinations are Maple files downloaded from…

Middle grades are a critical time for capturing the interest and imagination and developing the potential of mathematically promising students. This is a time for students to make sense of mathematics, build a solid foundation and enthusiasm, and set the course for the highest levels of mathematics in the future. This is a time to explore their…

High schools may still be anchored to 20th century expectations, but what are the critical guideposts for a 21st century high school education? There are many specific skills and competencies that young people will need to succeed, but more than particular skills, they will need the cognitive capacity to educate themselves throughout their entire…

Computer algebra systems are frequently used for research. In addition, some instructors have based entire advanced courses around these systems. One benefit is that they allow students to become familiar with the methods of calculus by individual experimentation. However, instructors have generally seen computer algebra systems as unsuitable for…

In the following general report the aim is to present a concise view of the organization, methods, and problems of the teaching of mathematics in the United States, touching particularly upon the larger questions that seem to merit especial emphasis, and referring to the special reports for details with respect lo the various types of schools. The…