Use matrices for storing and displaying information that can be presented in rows and columns, e.g. tables, databases, links in social or road networks.

A community centre records which of its five rooms (Art room, Boardroom, Computer lab, Dance studio, Equipment store) are accessible from each other by internal doors. The table shows the direct access between rooms. Which matrix correctly represents this information?

A regional library system has four branches: Northside (N), Eastside (E), Westside (W) and Central (C). The table shows the number of direct bus routes operating between branches. (a) Represent the bus route information as a 4×4 matrix. (b) Use your matrix to determine how many bus routes connect directly to the Eastside branch.