is a mathematical manipulative
often used to explore basic concepts in plane geometry
such as perimeter
or the characteristics of triangles
and other polygons
. Consisting of a physical board with a certain number of nails half driven in, in a symmetrical square
five-by-five array, students are encouraged to place rubber bands
around the pegs to model various geometric concepts or to solve other mathematical puzzles. Two-dimensional representations of the geoboard may be applied to ordinary paper using rubber stamps
or special "geoboard paper" with diagrams of geoboards may be used to help capture a student's explanations of the concept they have discovered or illustrated on the geoboard.
Geoboards were invented and popularized by Egyptian mathematician Caleb Gattegno in the 1950s.