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Formulas

Part of the Expressions & Data section of Coddy's Pre-Algebra journey. Lesson 8 of 51.

A formula is an expression that works something out. $F = \frac{9C}{5}+32$ changes degrees Celsius (C) into degrees Fahrenheit (F).

Put the number in place of the letter, then follow the order of operations. At 25 degrees Celsius: $F = \frac{9\cdot 25}{5}+32$ is $F = 45+32$ . That is 77 degrees Fahrenheit.

Challenge

On a cold night in Siberia it can be $-40$ degrees Celsius. What is that in Fahrenheit? Write F equal to the formula, with (-40) in place of C. Then work it out.

Start the lesson to read it in the interactive player and track your progress.

All lessons in Expressions & Data

1Variables and Expressions

What a Variable Is Writing Expressions Substituting a Value Expressions from Stories Recap: Expressions

4Combining Like Terms

Like Terms Letters and Numbers Negative Terms Two Letters Distribute, Then Collect Recap: Like Terms

7Probability

Chance as a Fraction The Complement Chance as a Percent Expected Count Recap: Probability

10Final Challenges

Final: Two Brackets Final: A Cubic Expression Final: The Phone Plan Final: A Decimal Mean Final: The Last Spin

2Evaluating Expressions

Negative Inputs Powers in ExpressionsFormulasRecap: Evaluating

5Patterns and Sequences

Continuing a Pattern The Common Difference The nth Term Writing the Rule Recap: Sequences

8Tables and Charts

Reading a Table Totals and Differences Reading a Line Graph Percent of a Total Recap: Tables and Charts

3The Distributive Property

Number Properties Mental Math Distributing Letters Distributing a Minus Recap: Distributing

6Data and Averages

The Mean Mean with Negatives The Median The Mode The Range Recap: Data and Averages

9Perimeter and Area

Perimeter Area of a Rectangle Area of a Triangle Perimeter as an Expression Recap: Perimeter and Area