NY Next Generation Math NY-3.MD.7.d
The Standard
Recognize area as additive. Find areas of figures composed of non-overlapping rectangles, and apply this technique to solve real world problems.
New York State Next Generation Mathematics Learning Standards
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students find the area of figures made from nonoverlapping rectangles by adding the areas of the parts. They choose a useful decomposition and apply it to real problems.
What Mastery Looks Like
- A student divides an L-shaped figure into two rectangles, finds each area, and adds them without overlap. The student labels the total in square units.
Common Misconceptions
- Students may double-count an overlap, leave a gap, or add side lengths instead of areas. They may use dimensions that belong to the whole figure for each part.
How to Assess It
- Give an L-shaped floor plan with all needed whole-number dimensions. Ask students to decompose it, find each rectangle's area, and total the result.
Lesson moves
Ways to Teach It
Cut composite paper figures into nonoverlapping rectangles, label dimensions, and add the separate areas.
Ask students how two different decompositions can produce the same total area.
Play composite-area exchange by drawing dimensioned figures for partners to decompose and solve.
Find flooring or garden area for a plan composed of two nonoverlapping rectangles.
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Printable NY-3.MD.7.d Worksheet
A ready-to-print activity worksheet aligned to NY-3.MD.7.d, with an answer key for the teacher on its own page. No account needed.
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Related Standards
- NY-6.G.1
Find area of triangles, trapezoids, and other polygons by composing into rectangles or decomposing into triangles and quadrilaterals. Apply these techniques in ...
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Recognize volume as additive. Find volumes of solid figures composed of two non-overlapping right rectangular prisms by adding the volumes of the non-overlappin...
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Apply the area and perimeter formulas for rectangles in real world and mathematical problems.
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