CCSS.Math.Content.6.EE.C.9
The standard
Use variables to represent two quantities in a real-world problem that change in relationship to one another; write an equation to express one quantity, thought of as the dependent variable, in terms of the other quantity, thought of as the independent variable. Analyze the relationship between the dependent and independent variables using graphs and tables, and relate these to the equation.
Common Core State Standards for Mathematics · Expressions and Equations
What this standard means
Students need to connect a real situation, a table, a graph, and an equation. They should name which variable changes on its own and which one depends on it. They also need to write an equation that shows the rule, make ordered pairs, graph them, and explain what points mean in context.
Mastery looks like moving both ways, from story to table to graph to equation, and back again. Students often mix up the variables, graph the axes backward, or write an equation that matches one row but not the whole pattern.
Ways to teach it
- Give pairs a cup-stacking task, record height for 1 to 6 cups, make a table, graph, and write an equation.
- Ask students to write: Which variable would you choose first, and which variable changes because of it? Explain using the problem.
- Use an exit ticket with a table of x and y values, asking students to write the equation and label independent and dependent variables.
- Connect to cell phone plans by comparing total cost to number of gigabytes used with a table, graph, and equation.
Plan a lesson for CCSS.Math.Content.6.EE.C.9
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Related standards
- CCSS.Math.Content.7.EE.B.4
Use variables to represent quantities in a real-world or mathematical problem, and construct simple equations and inequalities to solve problems by reasoning ab...
- CCSS.Math.Content.6.EE.B.6
Use variables to represent numbers and write expressions when solving a real-world or mathematical problem; understand that a variable can represent an unknown ...
- CCSS.Math.Content.6.EE.C
Represent and analyze quantitative relationships between dependent and independent variables.
- CCSS.Math.Content.HSA-CED.A.2
Create equations in two or more variables to represent relationships between quantities; graph equations on coordinate axes with labels and scales.