Objectives:

- Provide memorable awareness of incomplete distribution
- Provide a hook for defining “function” (each input produces a single, consistent output)
- Create intuitive understanding of input-output
- Answer the question, “When do we ever use these thought processes in real life jobs?” (answer: anyone who does any work with computer code)

Need: TI-83 or 84 calculators loaded with the 8-line program in **blue below.**

The plan: Student pairs are given the TI calculators. They are told there is something wrong with the program. Students run the program and see the answer is consistently wrong. They investigate the pattern and see it is incorrectly distributing 3 each time. Explain how they can see the code and coach them, as needed to fix the code.*

:**ClrHome** Do NOT type it in. Select ClrHome from CATALOG. This clears off the home screen.

**: Disp “F(X) = 3(x+ 4)”** Get Disp from CATALOG, then type the rest in: F(X) = 3(x+ 4) is displayed when the program runs.

**:Prompt X** Get Prompt from CATALOG, then type in X (either the variable X or the alpha X). This tells the calculator to display x=? and will then accept a number value for x.

**:3(x)+4→B** Type this using the same x used in Prompt x. Calculates input X and saves the result in B.*****

**:ClrHome ** clears the home screen

**:Output (4,5, “F(X)=3(x+4)”)** Get Output from CATALOG. This displays F(X)+3(x+4) on the 4th line of the home screen starting 5 spaces to the right.

**:Output (5,4, “OUTPUT:”)** Displays the word “OUTPUT” on the 5th line of the home screen starting 4 spaces from the right.

**:Output (5,12,B)** Displays the answer saved in B on line 5, 12 spaces from the left.

*This is the line with the bug. It should read : **3(x+4)→B**