Decomposing Rectangles to Find Area:
Page 1) Cut apart six 3x4 rectangles to cover figures to show how area can be determined by actually (or mentally) breaking apart figures;
Page 2) Area is the same in equally sized and divided rectangles if same portion is chosen.
Page 3) Determine and choose numerical expressions of area of figures marked with measurement of sides (not square units) using multiplication and addition.
Page 4) Determine numerical expressions of area of composite rectangles and add to find area. Draw composite rectangles using numerical expressions and compute total area.
Page 5) Students use 8 figures drawn with grids visible to decompose shapes and multiplication to find the area.
Page 6) Students do a duplicate of Pg 5, but without the grid.
Page 7) 8 new shapes are given without the grid visible. However, all sides are labeled.
Page 8) 8 new shapes are given, but without the grid, and many of the sides are unlabeled.
Page 9) Answer Sheet (24 figures) for 5, 6, 7, and 8 provided.
3.MD.7.a Find the area of a rectangle with whole-number side lengths by tiling it, and show that the area is the same as would be found by multiplying the side lengths.
3.MD.7.b Multiply side lengths to find areas of rectangles with whole-number side lengths in the context of solving real world and mathematical problems, and represent whole-number products as rectangular areas in mathematical reasoning.
3.MD.7.c Use tiling to show in a concrete case that the area of a rectangle with whole-number side lengths a and b+ c is the sum of a x b and a x c. Use area models to represent the distributive property in mathematical reasoning.
3.MD.7.d Recognize area as additive. Find areas of rectilinear figures by decomposing them into non-overlapping rectangles and adding the areas of the non-overlapping parts, applying this technique to solve real world problems.
3.6.C Determine the area of rectangles with whole number side lengths in problems using multiplication related to the number of rows times the number of unit squares in each row.
3.6.D Decompose composite figures formed by rectangles into non-overlapping rectangles to determine the area of the original figure using the additive property of area.
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