Geometry

Big Ideas

Identify and draw rhombuses, parallelograms, trapezoids, rectangles, and squares as examples of quadrilaterals, as well as examples of quadrilaterals that do not belong to any of these subcategories

Classify and sort 3D figures, including cones, cylinders, spheres, triangular and rectangular prisms, and cubes

Decompose composite figures formed by rectangles into non-overlapping rectangles to determine the area of the original figure using the additive property of area

Identify and draw rhombuses, parallelograms, trapezoids, rectangles, and squares as examples of quadrilaterals, as well as examples of quadrilaterals that do not belong to any of these subcategories

• Ask your child to name and draw all the quadrilaterals she can think of (e.g., square, rectangle, parallelogram, trapezoid, and rhombus). Alternatively, prompt her to draw a quadrilateral and then ask someone else to name it.

Classify and sort 2D and 3D figures, including cones, cylinders, spheres, triangular and rectangular prisms, and cubes

• Go on a shape hunt around the town. Challenge your child to spot as many shapes as he/she can and name the attributes that define the shape. For example, he/she might spot a street sign and say, “I see a rectangle! It has 4 sides and 4 right angles!”
• Give your child a handful of toothpicks or straws and encourage her to create two-dimensional shapes (e.g., triangle, parallelogram, pentagon). As she creates each shape, ask her to identify it and describe its attributes. For example, “This is a triangle because it has 3 sides and 3 angles.”
• Invite your child to construct a cube using toothpicks and 16 pieces of a sticky material such as mini marshmallows or gumdrops. As he builds, ask your child questions about its attributes: “How many faces does it have? How many corners? How many edges? What shape are the faces?” Then make other 3D figures.

Decompose composite figures formed by rectangles into non-overlapping rectangles to determine the area of the original figure using the additive property of area

• Give your child a pad of square sticky notes and let her practice tiling the area of rectangular surfaces, such as a place mat, a kitchen cupboard, the top of a small table or desk, or a window. How many sticky notes can fit without any gaps or overlaps? Find out by counting the sticky notes! Try this with different sizes of square sticky notes, and talk about why the number of sticky notes is different for the same objects.
• Give your child some graph paper. (You can find free graph paper online to print, or ask your child’s teacher for some.) Ask your child to design a public place of her choice by using rectangles drawn to scale. She might choose to design a skate park, a mall, a community garden, or whatever else sparks her imagination. Help your child determine the side lengths of the rectangles and calculate the area of the design.