Getting Started 
Misconception/Error The student does not have a correct strategy to determine the area of the figure. 
Examples of Student Work at this Level The student:
 Calculates the perimeter of the outside and inside rectangles (or the sum of those perimeters).
 Calculates the area of only the outside (or inside) rectangle.
 Multiplies all the values from the diagram.
 Combines the values from the diagram with some other combination of operations, such as subtracting the perimeter of the inside rectangle from the area of the outside rectangle.
 Does not provide enough work (or clarity in their work) to determine the solution strategy.

Questions Eliciting Thinking What is the problem asking? What is your plan for finding the area of the walkway?
How will determining the perimeter help you?
Why did you calculate the area of one of the rectangles and the perimeter of the other?
Is there a formula for finding the area of this shape?
Can you explain the steps you have taken in your calculations? 
Instructional Implications Ensure that the student is familiar with rectangles and the terms used to describe their dimensions such as base and height. If needed, review area and perimeter. Reinforce that perimeter is a linear measurement determined by adding the lengths of all the sides while area is measured in square units and is a measure of the surface contained in the interior of a polygon.
Explain that the area of a shape with interior portions missing can be found by subtracting the area of the missing portion from the area of the larger shape. Guide the student to calculate the area of each rectangle and to subtract the area of the interior rectangle from the area of the exterior rectangle. Next decompose the walkway into rectangles, label their dimensions, and guide the student to find and sum the areas of the component rectangles. Show the student that the two strategies result in the same area.
Provide additional opportunities to find the area of shapes that have interior sections missing. For example, provide a diagram of a triangle inside a rectangle along with needed dimensions. Ask the student to find the area outside the triangle but inside the rectangle. Encourage the student to show all work neatly and completely and to label the answer with the appropriate unit. 
Moving Forward 
Misconception/Error The student makes conceptual errors in decomposing the figure and calculating the area. 
Examples of Student Work at this Level The student demonstrates an understanding of decomposing into rectangles to find area, but is not able to correctly calculate the area. The student:
 Finds the area of the larger and smaller rectangles, then:
 Calculates their sum, rather than their difference.
 Writes them as two individual answers.
 Finds the areas of four individual, smaller rectangles, but:
 Does not find their sum.
 Uses one or more incorrect values to find these areas (e.g., miscalculates the walkway width, using six instead of three).
 Finds the area of the four trapezoids that compose the â€śframeâ€ť of the walkway, but uses six rather than three for the height of the trapezoid (i.e., walkway width).

Questions Eliciting Thinking Why did you add the areas of the large and small rectangles together (or not add the four individual areas together)?
Can you outline each of the decomposed shapes and label the dimensions?
What is the question asking you to determine? Can you show me in the picture what area you need to find?
How did you determine the width of the walkway (the trapezoid height)? Can you look at it again? 
Instructional Implications Using the studentâ€™s strategy, model a correct method for finding the area of the walkway. For example, explain that the area of a shape with interior portions missing can be found by subtracting the area of the missing portion from the area of the larger shape. Guide the student to calculate the area of each rectangle and to subtract the area of the interior rectangle from the area of the exterior rectangle. Then guide the student to decompose the walkway into rectangles, label their dimensions, find each area and sum the areas to result in the area of the walkway. Ask the student to check that both approaches resulted in the same area.
Provide additional opportunities to find the area of shapes that have interior sections missing. For example, provide a diagram of a triangle with several rectangular shapes removed. Ask the student to find the area of the triangular shape. Encourage the student to show all work neatly and completely and to label the answer with the appropriate unit. 
Almost There 
Misconception/Error The student makes minor mathematical errors. 
Examples of Student Work at this Level The student makes a minor error in computation or labeling units. The student:
 Calculates incorrectly in one step of the problem but all other work is correct.
 Transposes a number from one step to the next.
 Has a clear and correct strategy, but omits one step of the process.
 Uses the wrong units or no units at all.
 Writes rather than 336 .
 Writes a mathematically incorrect statement in some step of the work [e.g., writes multiple steps together into one long (incorrect) equation: 22 x 40 = 880 â€“ 544 = 336].

Questions Eliciting Thinking Can you check your work for errors?
What units should be used in this problem? Why?
How is different from 336 ? What does each mean?
Does 22 x 40 = 336? Can you show your work in individual steps? 
Instructional Implications Review multidigit multiplication and division and order of operations as needed.
Provide specific feedback concerning the error(s) made and ask the student to revise his or her work. Provide additional opportunities for the student to compose and decompose shapes and use formulas to find the areas of polygons.
Consider implementing the MFAS task Lost KeyÂ for further practice decomposing compound shapes. 
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 finds a total area of 336 for the area of the walkway around the swimming pool. The student may have found this area by:
 Calculating the area of the interior rectangle and subtracting it from the area of the exterior rectangle.
 Decomposing the walkway into four (or more) smaller rectangles (or trapezoids) and summing the areas of these sections.

Questions Eliciting Thinking Can you think of a different way you could have found the area?
Could you solve the problem if you were not given one of the measurements, for example, the width of the larger rectangle? 
Instructional Implications Provide additional opportunities to find the area of shapes that have interior sections missing. Include examples in which some dimensions must first be determined in order to find area.
Consider implementing other MFAS tasks from the standard. 