Academic standards

- CCSS.Math.Content.6.EE.A.2
- Write, read, and evaluate expressions in which letters stand for numbers.
- CCSS.Math.Content.6.EE.B.7
- Solve real-world and mathematical problems by writing and solving equations of the form x + p = q and px = q for cases in which p, q and x are all...
- CCSS.Math.Content.6.EE.B.8
- Write an inequality of the form x > c or x < c to represent a constraint or condition in a real-world or mathematical problem. Recognize that...
- CCSS.Math.Content.6.EE.C.9
- Use variables to represent two quantities in a real-world problem that change in relationship to one another; write an equation to express one...
- CCSS.Math.Content.7.RP.A.2
- Recognize and represent proportional relationships between quantities.
- CCSS.Math.Content.8.EE.B.5
- Graph proportional relationships, interpreting the unit rate as the slope of the graph. Compare two different proportional relationships...
- CCSS.Math.Content.8.EE.B.6
- Use similar triangles to explain why the slope m is the same between any two distinct points on a non-vertical line in the coordinate plane; derive...
- CCSS.Math.Content.8.F.A.3
- Interpret the equation y = mx + b as defining a linear function, whose graph is a straight line; give examples of functions that are not linear. For...
- CCSS.Math.Content.8.SP.A.3
- Use the equation of a linear model to solve problems in the context of bivariate measurement data, interpreting the slope and intercept. For...
- GLE 0606.1.1
- Use mathematical language, symbols, and definitions while developing mathematical reasoning.
- GLE 0606.3.2
- Interpret and represent algebraic relationships with variables in expressions, simple equations and inequalities.
- GLE 0606.3.4
- Use expressions, equations and formulas to solve problems.
- GLE 0606.3.5
- Use multiple representations including symbolic algebra to model and/or solve contextual problems that involve linear relationships.
- GLE 0706.2.3
- Develop an understanding of and apply proportionality.
- GLE 0706.3.5
- Understand and graph proportional relationships.
- GLE 0706.3.6
- Conceptualize the meanings of slope using various interpretations, representations, and contexts.
- GLE 0706.3.7
- Use mathematical models involving linear equations to analyze real-world phenomena.
- GLE 0806.3.4
- Translate among verbal, tabular, graphical and algebraic representations of linear functions.
- GLE 0806.5.2
- Select, create, and use appropriate graphical representations of data (including scatterplots with lines of best fit) to make and test conjectures.
- SPI 0606.3.1
- Represent on a number line the solution of a linear inequality.
- SPI 0606.3.3
- Write equations that correspond to given situations or represent a given mathematical relationship.
- SPI 0606.3.5
- Translate between verbal expressions/sentences and algebraic expressions/equations.
- SPI 0706.1.3
- Recognize whether information given in a table, graph, or formula suggests a directly proportional, linear, inversely proportional, or other nonlinear relationship.
- SPI 0706.3.1
- Evaluate algebraic expressions involving rational values for coefficients and/or variables.
- SPI 0706.3.4
- Interpret the slope of a line as a unit rate given the graph of a proportional relationship.
- SPI 0706.3.5
- Represent proportional relationships with equations, tables and graphs.
- SPI 0806.1.3
- Calculates rates involving cost per unit to determine the best buy.
- SPI 0806.3.4
- Translate between various representations of a linear function.
- SPI 0806.3.7
- Identify, compare and contrast functions as linear or nonlinear.
- SPI 0806.5.3
- Generalize the relationship between two sets of data using scatterplots and lines of best fit.
- TSS.Math.6.EE.A.2
- Write, read, and evaluate expressions in which variables stand for numbers.
- TSS.Math.6.EE.B.7
- Solve real-world and mathematical problems by writing and solving onestep equations of the form x + p = q and px = q for cases in which p, q, and x are all...
- TSS.Math.6.EE.B.8
- Interpret and write an inequality of the form x > c or x
- TSS.Math.6.EE.C.9
- Use variables to represent two quantities in a real-world problem that change in relationship to one another.
- TSS.Math.7.RP.A.2
- Recognize and represent proportional relationships between quantities.
- TSS.Math.8.EE.B.5
- Graph proportional relationships, interpreting the unit rate as the slope of the graph. Compare two different proportional relationships represented in...
- TSS.Math.8.EE.B.6
- Use similar triangles to explain why the slope m is the same between any two distinct points on a non-vertical line in the coordinate plane; know and derive...
- TSS.Math.8.F.A.3
- Know and interpret the equation y = mx + b as defining a linear function, whose graph is a straight line; give examples of functions that are not linear.
- TSS.Math.8.SP.A.3
- Use the equation of a linear model to solve problems in the context of bivariate measurement data, interpreting the slope and intercept. For example, in a...

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Essential and guiding questions:

Questions for Students:

- Can you think of a situation where there might be a positive slope for profit on items selling on eBay?
- What other kinds of items might sell for high prices in the future?
- How fast do you think the lines of profit for other items would come down?
- Do you think the profit and closing bids will always have an approximately linear relationship?