
Balance Scale Algebra
Lola Bell
4th grade
Oglethorpe County Elementary School
Oglethorpe County Schools
Task

Overview
In this activity, students find an unknown quantity, explore the relationship between quantities, and enhance their understanding of the equal sign as equivalence and balance.
Illustrative Task
 Using the balance scale design and set of 3D geometric figures, students will set up the balance scale according to the teacher’s directions. Students use symbols for the unknown weights to write a number sentence that represents the balanced scale. Then, find the missing weights.
 Using only geometric figures (and no numbers) students will set up the balance scale according to the teacher’s directions. Students use symbols for the unknown weights to write a number sentence that represents the balanced scale. Then, students describe the relationship between one cylinder and one rectangular prism.


GPS Addressed

M4A1. Students will represent and interpret mathematical relationships in quantitative expressions.
 Understand and apply patterns and rules to describe relationships and solve problems.
 Represent unknowns using symbols, such as and △
 Write and evaluate mathematical expressions using symbols and different values.


Video Information


Use these questions to guide your thinking about some of the important teacher ideas in the lesson featured in the video clip.
 What kinds of questions does the teacher ask to promote students’ problem solving?
 How is the teacher gauging students’ current understandings and building from those understandings?
 Consider the GPS standards listed with this video.
 What makes this lesson different from lessons you have taught on this topic?


