The document provides an introduction to matrices, including: - Matrices are rectangular arrays of elements displayed in rows and columns. They can represent transformations, systems of equations, and more. - The order or size of a matrix is the number of rows and columns. For example, an m x n matrix has m rows and n columns. - Common types of matrices include row matrices, column matrices, square matrices, diagonal matrices, symmetric matrices, and more. - Basic matrix operations include addition, subtraction, and multiplication. Properties like commutativity and distributivity apply. - Matrices have applications in fields like biology, chemistry, and more. They can model structures like extracellular matrices and crystal structures.