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Formula Library

Try prototype

  

Design Overview

  • Evaluates an expression given all parameters.
  • Solves an equation with one unknown.
  • Ability to add custom formulas.
  • Ability to check answers.


Motivation

  • Formulas such as the quadratic formula are used frequently in Algebra 1. Evaluating formulas with one unknown is common task in Algebra 1.
  • 7 of 9 Algebra 1 teachers encourage their students to check answers using the calculator.

Major findings

  • 3/3 users were confused by the "Incorrect" feedback that appeared while entering the equation.
  • 2/3 users were able to complete a problem using the quadratic formula.

Past iterations and user tests

See Evolution of Prototypes

Design Background

Since our textbook analyses indicated that students need many formulas in Algebra 1, our design helps the student keep track of these formulas by storing them directly in the calculator. We also found that students frequently used the calculators to check their answers, and that teachers encouraged this behavior. Thus we modified the equation solving portion of the design to include an answer checker that allows the student to input a proposed answer and get a correct/incorrect response from the calculator.

Design Walkthrough

1.

"Quadratic Formula" is selected.
2.

After entering the parameters, the screen shows the answer(s).

To solve for 1 unknown:

 

1.

User selects "Custom Formula" from the menu to enter a formula that does not currently exist. User enters the equation using the text screen and keys on the calculator.
2.

The user fills in known values in the equation and the press "Enter" to solve. The calculator would fill in a "?" for the missing unknown.

3.

The answer is displayed and highlighted.

To check an answer:

 

4.

The user may enter all values to check if some values satisfy the equation.
5.

The user fills in known values in the equation and the press "Enter" to solve. The calculator would fill in a "?" for the missing unknown.

6.

Pressing "Enter" would indicate whether the values satisfy the equation.