by Kimiko Ryokai and Timothy CharoenyingMathMarks is a mobile augmented reality system that invites children to tag their environment with markers and explore math concepts such as length, area, perimeter, and variables. Our goal is to help children explore and think about abstract math concepts with the help of their familiar physical environment. Specifically, we envision a mathematics classroom in which students can seamlessly identify mathematical properties and relationships in and between the objects existing in the world around them. MathMarks System 1) Line, Perimeter, and Area ModeIn this basic mode, the system displays the lines between the markers. When more than 3 markers are present, it displays the geometric shape created by the markers, i.e., triangles or quadrilaterals (see the yellow triangle and rectangle in the figures below). The system calculates and displays the actual length between the markers (both in inches and centimeters), as well as the area and perimeter of a given geometric figure.
2) Grid ModeGrid mode (activated by pressing "g" key) overlays upon the shape identified by the system. The idea is to illustrate for students the mathematical bases for describing the area of a twodimensional shape in terms of "square units." A student might create a shape with a width and height of 10 inches. Upon activating grid mode, the student may see at 10 by 10 inch grid comprised of 100 individual 1x1 inch squares units.

