Equality Explorer: Two Variables

Equality Explorer: Two Variables Screenshot
  • Equations
  • Inequalities
  • System of Equations

Topics

  • Equations
  • Inequalities
  • System of Equations

Description

Explore what it means for a mathematical statement to be balanced or unbalanced by interacting with integers and variables on a balance. Find multiple ways to balance x and y to build a system of equations.

Sample Learning Goals

  • Solve and manipulate algebraic equations by substituting different values for a variable
  • Use a balance model to solve an equation for an unknown, and justify your strategies for solving
  • Build a system of equations
  • Determine the solution set of a system of equations

Standards Alignment

Common Core - Math

6.EE.B.5
Understand solving an equation or inequality as a process of answering a question: which values from a specified set, if any, make the equation or inequality true? Use substitution to determine whether a given number in a specified set makes an equation or inequality true.
6.EE.B.6
Use variables to represent numbers and write expressions when solving a real-world or mathematical problem; understand that a variable can represent an unknown number, or, depending on the purpose at hand, any number in a specified set.
7.EE.B.3
Solve multi-step real-life and mathematical problems posed with positive and negative rational numbers in any form (whole numbers, fractions, and decimals), using tools strategically. Apply properties of operations to calculate with numbers in any form; convert between forms as appropriate; and assess the reasonableness of answers using mental computation and estimation strategies. For example: If a woman making $25 an hour gets a 10% raise, she will make an additional 1/10 of her salary an hour, or $2.50, for a new salary of $27.50. If you want to place a towel bar 9 3/4 inches long in the center of a door that is 27 1/2 inches wide, you will need to place the bar about 9 inches from each edge; this estimate can be used as a check on the exact computation.
7.EE.B.4
Use variables to represent quantities in a real-world or mathematical problem, and construct simple equations and inequalities to solve problems by reasoning about the quantities.
8.EE.C.7
Solve linear equations in one variable.
8.EE.C.7a
Give examples of linear equations in one variable with one solution, infinitely many solutions, or no solutions. Show which of these possibilities is the case by successively transforming the given equation into simpler forms, until an equivalent equation of the form x = a, a = a, or a = b results (where a and b are different numbers).
8.EE.C.8
Analyze and solve pairs of simultaneous linear equations.
HSA-CED.A.1
Create equations and inequalities in one variable and use them to solve problems. Include equations arising from linear and quadratic functions, and simple rational and exponential functions.
HSA-CED.A.3
Represent constraints by equations or inequalities, and by systems of equations and/or inequalities, and interpret solutions as viable or nonviable options in a modeling context. For example, represent inequalities describing nutritional and cost constraints on combinations of different foods.
HSA-REI.A.1
Explain each step in solving a simple equation as following from the equality of numbers asserted at the previous step, starting from the assumption that the original equation has a solution. Construct a viable argument to justify a solution method.
HSA-REI.B.3
Solve linear equations and inequalities in one variable, including equations with coefficients represented by letters.
Version 1.0.12

Teacher Tips

Download teacher tips PDF Overview of sim controls, model simplifications, and insights into student thinking ( PDF ).

Teacher-Submitted Activities

Middle School Math Sim Alignment This contribution was designed by PhET. Amanda McGarry MS Other Mathematics
SECUNDARIA: Alineación PhET con programas de la SEP México (2011 y 2017) This contribution was designed by PhET. Diana López MS
HS
Other Chemistry
Physics
Mathematics
Biology
PREPARATORIA: Alineación de PhET con programas de la DGB México (2017) This contribution was designed by PhET. Diana López HS
UG-Intro
Other Chemistry
Mathematics
Physics

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Chinese (Simplified) All 中文 (中国) Run now 等式探索:两个变量
Chinese (Traditional) All 中文 (台灣) Run now Equality Explorer: Two Variables_探索等式:兩個變數
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iPad:
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iPad compatible sims

Android:
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Chromebook:
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Chromebook compatible sims

Windows Systems:
Microsoft Edge, latest version of Firefox, latest version of Google Chrome.

Macintosh Systems:
macOS 10.9.5+, Safari 9+, latest version of Chrome.

Linux Systems:
Not officially supported. Please contact phethelp@colorado.edu with troubleshooting issues.

Design Team Third-party Libraries Thanks To
  • Amanda McGarry (lead designer)
  • Chris Malley (developer)
  • Diana López Tavares
  • Ariel Paul
  • Kathy Perkins
  • Argenta Price
  • Beth Stade
  • David Webb
  • Mariah Hermsmeyer (graphic arts)
  • Cheryl McCutchan (graphic arts)
  • almond-0.2.9.js
  • base64-js-1.2.0.js
  • easing-equations-r12
  • FileSaver-b8054a2.js
  • font-awesome-4.5.0
  • game-up-camera-1.0.0.js
  • he-1.1.1.js
  • himalaya-0.2.7.js
  • jama-1.0.2
  • jquery-2.1.0.js
  • lodash-4.17.4.js
  • pegjs-0.7.0.js
  • seedrandom-2.4.2.js
  • text-2.0.12.js
  • TextEncoderLite-3c9f6f0.js
  • Tween-r12.js