10th Congress of the European-Society-for-Research-in-Mathematics-Education (CERME) -- FEB 01-05, 2017 -- Dublin, IRELANDHollebrands, Karen/0000-0001-8266-1467WOS: 000467053304127In this research study, we investigated how middle school students created 3-dimensional objects from 2-dimensional figures using an extrusion method. in a summer enrichment program, students used manipulatives and a dynamic geometry program (Cabri 3D). We identified students' strategies for forming 3-dimensional objects with a focus on their gestural signs. the results demonstrated that they most often employed dynamic-pointwise and dynamic-objectwise gestures to demonstrate the lateral faces or edges of 3-dimensional objects. Also, students linked their gestural signs and the Segment tool of Cabri 3D to indicate their reasoning.European Soc Res Math EducDivision of Undergraduate EducationNational Science Foundation (NSF)NSF- Directorate for Education & Human Resources (EHR) [1712280] Funding Source: National Science Foundatio
