Janet M. Sharp and Corrine Heimer
A series of lessons used to study basic ideas from spherical geometry.
Peter L. Glidden
Article describes the construction and use of the "fraction computer," a simple manipulative that helps pupils understand how to add and subtract fractions.
LaDawn Haws
An activity involving multilink blocks that helps students develop three-dimensional spatial skills. The activity is motivated by the work of Nobel Prize winner Dorothy Crowfoot Hodgkin.