Early algebra ideas involving one variable, Clip 1 of 11: Open sentences that can be made True or False with Legal or Illegal substitutions [video]. Retrieved from https://doi.org/doi:10.7282/T3XS5T98

DescriptionIn the first of eleven clips from the first day of the Early Algebra Ideas sessions, the researcher, Robert B. Davis, introduces ideas about algebraic equations with one variable and truth sets to a class of 6th grade students. Davis begins with the first problem statement printed below to introduce ideas about algebraic sentences or equations with one variable that can be true, false or open. The concept of a variable is introduced by varying the values that can be inserted into a printed ”box” that is a term within the equation. He introduces the idea of a truth set with brackets before demonstrating the mathematical Rule of Substitution, which says that in evaluating any mathematical expression or equation, if a variable appears more than once, for a legal substitution, the same value must be inserted into each “box”. Using the second problem statement below, which has two “boxes” in the equation, Davis asks the students for values to substitute into each “box” in order to create sentences that are legal and false; illegal and false; illegal and true; or legal and true. Observers present included researchers Amy Martino and Alice Alston and Kenilworth mathematics supervisor, Marcia O'Brien.
Problem Statements:
1. True, False or Open?
3 + □ = 5
Is there a number that would make the statement False/True?
Use { } Truth set – rather than “filling in the box and erasing it “.
3. Open sentences with two of the same variable (two “boxes”)
□ + □ = 8
Legal and false? Illegal and false? Illegal and true? Legal and true?

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.

Date Captured1999-09-30

Local IdentifierA54A55-ALG-PIB-CLIP001

Related Publication Type: Related publication Label: Ed.D. dissertation references the video footage that includes Early algebra ideas involving one variable, Clip 1 of 11: Open sentences that can be made True or False with Legal or Illegal substitutions. Date: 2009 Author: Spang, Kathleen E. (Rutgers Graduate School of Education)

Name: Teaching algebra ideas to elementary school children : Robert B. Davis' introduction to early algebra Reference: QA.S735 2009

Source Title: A54, Early algebra ideas involving one variable (teacher view), Grade 6, September 30, 1993, raw footage. Identifier: A54-19930930-KNWH-TV-CLASS-GR6-ALG-PIB-RAW