B63, Madison Project: Robert B. Davis Introducing Integers With Pebbles in the Bag (Presentation & classroom view), Grade 3-5, 1950s_1960s, Clip [video]. Retrieved from https://doi.org/doi:10.7282/T3GQ71Z9
DescriptionIn this 8 minutes whole class discussion about early algebra ideas (specifically with regards to integers), Researcher Robert B. Davis models adding positive and negative integers to a class of elementary school students by having the students add and remove stones from a bag. The actions involve one student giving a command “Go” and then a second student proposes the number of stones to be added or subtracted. Davis then responds to the children’s directions from the class by either adding or removing a specific number of stones to the bag based on the directions. Davis and the students describe each action with symbolic equations that designates addition as “adding more pebbles,” which they symbolize as ‘+’, and subtraction as “take away,” which they symbolize by ‘-‘ before the numeral to designate a negative number. Examples of the equations that the students construct to represent pebble actions are:
Toward the end of the session, using pebble actions, Davis leads the class to discuss the meaning of -3 and +3 using the expression 2-5. The whole class agrees that +3 means 3 more pebbles. The camera view focuses on the teacher and whole class.
RightsThe video is protected by copyright. It is available for reviewing and use within the Video Mosaic Collaborative (VMC) portal. Please contact the Robert B. Davis Institute for Learning (RBDIL) for further information about the use of this video.