The Jinx Puzzle
 
 
TEACHERS: The Jinx Puzzle
Overview:
 
This puzzle engages students through the use of technology and enhances their understanding in three areas:
  how equations can be solved in a spreadsheet
  how that spreadsheet can illustrate the equation in a graph
  how that graph is helpful for understanding the equation
   
Understanding these connections will help launch a unit on equations of 2 variables and a unit on graphing. 

NJ Core Curriculum Content Standards:

    • Solving equations (with 2 variables)

    • Problem solving

    • Slope

    • Graphing

    • Spreadsheets

    • Equation of a line
  • Standards?????

Materials:

Suggested Classroom Environment:

  • One computer classroom with projector or classroom lab

Procedure:

A. Setting the Stage

  1. Students should have a working understanding of order of operation and the use of variables to represent numbers.  This is a good lesson for starting a unit on equations or graphing.
  2. A student worksheet can be printed and prepared for students ahead of time.  This lesson can be done with the teacher leading the class using one computer and a projector or by guiding the students through building their own spreadsheet in which case enough computers will be necessary.  At most two students should be assigned to one computer.
    3.

B. Activity

  1. Hand out student worksheet, have students read it or read it aloud and explain the Jinx.
  2. Have students solve 2-3 problems by hand working individually or in pairs. 
  3. As a class compare results.  How many different numbers were tried?  What did everyone get?
  4. As a class or working in pairs, use a spreadsheet to extend computing power.  Specific Microsoft Excel directions have been provided.  Suggest students try big numbers and weird numbers. 
    1. Have students graph their results.  What is the equation of the line?
    2. For accountability have students print their trials and a graph with the equation of the line.
  5. As a class compare results.  How many different numbers were tried?  What did everyone get?
  6. Write out the equation outlined by this problem and solve it on the board.  Have students make suggestions on what to do to reduce the equation.

C. Debrief

  1. Perform Java Applet outline of the solution.   If you do not have access to the animation the presentation is below if you scroll down.  Alternatively you could use other manipulatives to demonstrate how the Jinx Puzzle works.
  2. Webpage version of the solution in the event that the Applet will not run:

Assessment:

Answers to the questions from the student worksheet:

Everyone try a number and let’s see what we get as a class!

Why is it called the Jinx Puzzle?

Cause you always get 13 which is considered by some to be an unlucky number. 

Do you think it will always work? Why do you think that?

What about weird numbers?  Do they work?

 Try negative numbers!  fractions!

How can we increase our computing powers?

 Use a computer!

Can you find a number that will not always end up as 13?

If not, why not?

 What about pi or e or square root of 2?

What is the equation of the line?

 y = 13

Let’s write out the equation and solve it!  Write out the equation starting from 'pick a number and add 11'.  It gets messy at first but does simplify to y=13.

Extensions / Related Activities:

 

 

 

 

 
 
 

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