Getting Started 
Misconception/Error The student is unable to decompose the solid in order to find its surface area. 
Examples of Student Work at this Level The student:
 Does not demonstrate an understanding that the areas of individual faces must be calculated and combined.
 Attempts to apply a single formula to calculate the surface area of the figure.

Questions Eliciting Thinking What is surface area? What do you have to do to find it?
Can you decompose the figure into familiar shapes? Can you find the area of a triangle (rectangle)? 
Instructional Implications Review the concept that the surface area of a solid 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 and threedimensional shapes. Ask the student to clearly identify the decomposed parts and any relevant dimensions. Review the process of finding surface area by constructing nets. Consider implementing the MFAS tasks for standard 6.G.1.4.
Be sure the student understands the distinction between area and surface area and review both concepts, as needed. Ensure that the student is familiar with the terms base, face, height, and edge. If necessary, review area formulas and ensure the student understands that the surface area of a prism can be calculated by adding the areas of its component parts. Guide the student in systematically decomposing the prism into familiar shapes. Ask the student to label relevant dimensions and calculate the areas.
Provide manipulatives 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 figures into nets and creating other strategies to calculate surface area. Provide additional opportunities for the student to decompose figures and calculate surface area. Include scenarios involving whole numbers, fractions, and decimals.
Consider implementing other MFAS tasks for standard 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 solid but:
 Assumes that the three rectangular faces of the prism have the same areas.
 Uses an incorrect formula or procedure to calculate area of a component.
 Consistently uses incorrect values in formulas.

Questions Eliciting Thinking How many faces does this figure have? Can you describe them?
What does it mean for a triangular prism to be a right triangular prism? What does that tell you about the shapes of the faces? What does it tell you about the triangular faces?
Do all of the rectangular faces have the same dimensions?
How do you find the area of a triangle? What measurements do you need? 
Instructional Implications Be sure the student understands the distinction between area and surface area and review both concepts, as needed. Ensure that the student is familiar with the terms base, face, height, and edge. If necessary, review area formulas and ensure the student understands that the surface area of a prism can be calculated by adding the areas of its components.
Guide the student through a systematic analysis of the surface area of the prism. Using the solid on the worksheet, prompt the student to identify and label every length measurement that can be determined and identify those needed to calculate areas.
Provide additional opportunities for the student to find the surface area of solids and composite figures. Guide the student in systematically decomposing the figures into familiar shapes. Ask the student to label relevant dimensions and calculate the areas.
Provide practice problems in which insufficient information is given to calculate surface area, and ask the student to identify which additional measurement is needed in order to solve the problem.
Consider implementing the MFAS task Composite Surface 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 but:
 Makes a calculation error when summing the areas of the component shapes.
 Neglects to sum all of the areas of the component shapes.
 Makes a multiplication error when calculating an area.
 Neglects to label units or labels them incorrectly (e.g., as linear or cubic units).

Questions Eliciting Thinking I think you may have made a calculation error. Can you check your work?
What one value represents the surface area of the prism?
How should the units be labeled? 
Instructional Implications Provide specific feedback and allow the student to revise his or her work.
Provide additional practice opportunities. Include shapes whose dimensions are given by fractions and decimals. 
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 successfully decomposes the figure into familiar shapes, selects appropriate formulas for calculating area, and accurately calculates the surface area as 1608 .

Questions Eliciting Thinking How did you determine the measurements of each of the quadrilateral faces? How did you calculate the areas of the triangular faces?
What does it mean for the prism to be a right prism? What does that tell you about the faces? 
Instructional Implications Represent the dimensions of the figure with variables and challenge the student to write a single expression for finding the surface area of the composite figure.
Provide practice problems involving composite figures with fractional edge lengths and problems in which surface 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 surface area.
Consider implementing other MFAS tasks for standard 7.G.2.6. 