Getting Started 
Misconception/Error The student is unable to decompose the figure in order to find its area. 
Examples of Student Work at this Level The student:
 Attempts to apply a single formula to determine the area of the figure, multiplying base times height.
 Decomposes the figure into shapes whose areas he or she cannot calculate.
 Attempts to calculate something other than the area (e.g., perimeter).
 Attempts to calculate area but makes errors and then calculates an average area.

Questions Eliciting Thinking What is area? How is it determined?
Is there a single formula for area that will work for this figure?
Can you decompose the figure into familiar shapes?
Why did you calculate average area? What is the question asking for? 
Instructional Implications Review the concept that the area of a composite figure can be found by decomposing the figure into familiar shapes and finding the areas of the parts. Provide opportunities for the student to decompose both twodimensional and threedimensional figures into familiar twodimensional shapes. Ask the student to clearly identify the decomposed parts and any relevant dimensions. Guide the student in systematically decomposing the figure into familiar shapes. Ask the student to label relevant dimensions and calculate the area of each. Provide manipulatives such as pattern blocks for the student to explore in order to gain handson experience with decompositions of composite figures. Partner the student with a classmate to practice decomposing shapes into familiar figures and creating strategies to calculate area.
Provide additional opportunities for the student to decompose shapes and use formulas to calculate area. Include scenarios involving whole numbers, fractions, decimals, ratios, and conversions of various units of measure within the same system.
Consider implementing the MFAS task Octagon Area (7.G.2.6). 
Moving Forward 
Misconception/Error The student makes significant errors when calculating areas. 
Examples of Student Work at this Level The student demonstrates an understanding of the need to decompose the figure but:
 Uses an incorrect formula or procedure to determine area.
 Uses an incorrect length when substituting into a formula.
 Attempts to estimate the area of each decomposed figure by counting.

Questions Eliciting Thinking What shape is this? How do you calculate the area of this shape?
What measurements do you need to calculate the area of this shape? Can you determine the dimensions if they are not given?
Do you know a formula to find the area of this shape?
What problems did you have when estimating the area by counting? How could you find the exact area? 
Instructional Implications Ask the student to clearly identify the decomposed parts and any relevant dimensions. Guide the student in systematically decomposing the figure into familiar shapes. Ask the student to label relevant dimensions and calculate the areas.
Provide additional opportunities for the student to decompose shapes and use formulas to calculate area. Include scenarios involving whole numbers, fractions, decimals, ratios, and conversions of various units of measure within the same system.
Consider implementing the MFAS task Octagon Area (7.G.2.6). 
Almost There 
Misconception/Error The student makes a minor mathematical error. 
Examples of Student Work at this Level The student successfully decomposes the figure into familiar shapes and selects appropriate formulas for calculating area. However, the student:
 Makes a multiplication error when calculating component areas.
 Neglects to sum the areas of the component figures.
 Makes a calculation error when summing the areas of the component figures.
 Labels units incorrectly or not at all.

Questions Eliciting Thinking I think you made a calculation error. Can you check your work?
How can you find the one value that represents the total area of the figure?
What units are given in the problem? How should the units be labeled for area? 
Instructional Implications Provide specific feedback and allow the student to revise his or her work.
Provide additional opportunities for the student to decompose shapes and use formulas to calculate area. Include scenarios involving whole numbers, fractions, decimals, ratios, and conversions of various units of measure within the same system. 
Got It 
Misconception/Error The student provides complete and correct responses to all components of the task. 
Examples of Student Work at this Level The student decomposes the figure and calculates the total area as 74 square feet.

Questions Eliciting Thinking How did you determine the area of the figure? What measurements did you need? How did you find the measurements you needed? What additional sections did you need to decompose? 
Instructional Implications Represent the dimensions of the figure with variables and challenge the student to write a single expression for finding the area of the composite figure.
Provide practice problems involving composite figures with fractional edge lengths and problems in which area is given and the student must identify a missing measurement.
Provide opportunities for the student to explore how changing a dimension of a figure affects the area.
Consider implementing other MFAS tasks for standard 7.G.2.6 that involve surface area and volume of three dimensional shapes. 