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Emily Boyle
Emily Boyle
(Bear Creek - United States)

Down to Business - Rewriting Formulas

Take-Home Quiz,In-Class Activity

Time required: 30 minutes

Materials: calculators

Objectives: Substitute given values into an equation and solve for the missing value. Solve literal equations for a given variable

Prerequisites: Evaluating expression Solving linear equations Using the distributive property to do simple factoring (ex. P + Prt = P(1 + rt)) Solve literal equations for a given variable (an introduction to the topic)

Description: Students often do not see the point in solving formulas for a particular variable when there are no values given. This lab is not designed to teach how to solve literal equations, but rather to give students an understanding of why one might need to do so.

This lab has students substitute values into the basic interest formula and then solve for the missing value. After solving several problems in this form, they solve the formula for that variable and then evaluate it by substituting in the given information. Students discover for themselves that it is sometimes better to solve for the variable first and then input the values when solving several problems for the same variable.

Teaching notes: This is not intended to teach students how to solve literal equations, but to give them a reason to do so.

Additional formulas have been submitted by the Chemistry Department as ones that their students are required to manipulate.

*Implementation: This lab can be used as an in-class follow-up activity after students have been introduced to the topic. This lab can be used as a take-home activity to reinforce the need to solve literal equations.

*Follow Up/ Discussion Questions: What are the advantages of rewriting a formula in an equivalent form? When would it make 'sense' to rewrite the formula rather than just substituting in the given values and solving?

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