Developing School Algebra Through A Focus on Functions and Applications

1. Developing School Algebra Through A Focus on Functions and Applications

2. Results from focusing on the “dance of symbols” • Fragile mastery of limited technical skills; • Training in special procedures for solving inauthentic problems; • Strong distaste for the subject

3. Rethinking the roles of variables, expressions, and equations. • Variables are quantities that change over time and in response to change in other quantities; • Equations represent relationships among quantities; • Expressions represent algorithms for calculating values of dependent variables.

4. Algebra in Context

5. Variables and Relationships to Consider Ticket price, tickets sold, income, expenses, profit, … Demand: n(x) = 5000 – 65x Income: I(x) = 5000x – 65x2 Expenses: E(n) = 4n + 25,000 E(x) = 45,000 – 260x Profit: P(x) = – 65x2 + 5260x – 45,000

6. Alternative Solution Options

7. Alternative Solution Options

8. Alternative Solution Insights

9. What ideas give coherence to algebrain secondary school mathematics? The most important goals of algebraic reasoning are understanding and predicting patterns of change in variables.

10. What ideas give coherence to algebrain secondary school mathematics? The letters, symbolic expressions, and equations or inequalities of algebra are tools for representing what we know or what we want to figure out about a relationship between variables.

11. What ideas give coherence to algebrain secondary school mathematics? Algebraic procedures for manipulating symbolic expressions into equivalent forms are also means to the goal of insight into relationships between variables. Calculating tools offer powerful alternative methods to gain insight and solve problems.

13. Essential dispositions, understanding, and skills: Disposition to look for key quantitative variables in problem situations and relationships among variables that reflect cause-and-effect, change-over-time, or pure number patterns.

14. Essential dispositions, understanding, and skills: A repertoire of significant and common patterns to look for—direct and inverse variation, linearity, exponential change, quadratic patterns, etc.

15. Essential dispositions, understanding, and skills: Ability to represent relationships between variables in words, graphs, data tables and plots, and symbolic expressions.

16. Essential dispositions, understanding, and skills: Ability to draw inferences from represented relationships by estimation from tables and graphs, by exact reasoning using symbolic manipulations, and by insightful interpretation of symbolic forms.

17. Essential dispositions, understanding, and skills: Judgment to translate deductions back to the original problem situations with reasoned sensitivity to limitations of the original modeling process.

18. Reasonable Concerns • Is this “algebra”? • Does the function-oriented development serve well the variety of topics in which algebraic manipulation is useful? • Don’t users of CAS need some personal skill to understand how to utilize the tool? • Are CAS tools flexible enough and adaptable enough to serve all problem solving needs? • Is “just in time” skill development feasible pedagogically?