In the second grade lessons, students extend their study of shapes to quadrilaterals and pentagons. They begin to recognize parallelograms, trapezoids, rectangles, and squares as special cases of quadrilaterals. They review the names and attributes of solid shapes introduced in kindergarten (cube, cone, cylinder, and sphere) and first grade (prism) and then analyze attributes of solid shapes. The foundation for the concept of area is developed by having students partition rectangles into rows and columns of same-size squares counting the number of squares into which a rectangle has been partitioned. Students observe the relationship between the size of the square into which a rectangle has been partitioned and the number of resulting squares. They partition circles and rectangles into two, three, or four equal shares and use the words* halves*, *thirds*, *fourths*, and *quarters *to describe the parts. They recognize that equal shares of two circles are the same only when they come from identical circles and that two equal shares of identical wholes need not have the same shape.

- CCSS.MATH.CONTENT.2.G.A.1
- CCSS.MATH.PRACTICE.MP3

- Basic Shapes: Circles
- Basic Shapes: Polygons
- Basic Shapes: Quadrilaterals
- Basic Shapes: Triangles

- CCSS.MATH.CONTENT.2.G.A.1
- CCSS.MATH.PRACTICE.MP2

- Basic Shapes: Right Solids

- CCSS.MATH.CONTENT.2.G.A.1
- CCSS.MATH.PRACTICE.MP2
- CCSS.MATH.PRACTICE.MP3
- CCSS.MATH.PRACTICE.MP6

- Angle Tester
- Basic Shapes: Circles
- Basic Shapes: Polygons
- Basic Shapes: Quadrilaterals
- Basic Shapes: Triangles
- Parallel Line Tester

- CCSS.MATH.CONTENT.2.G.A.3
- CCSS.MATH.PRACTICE.MP2

- Partitioning Circles

- CCSS.MATH.CONTENT.2.G.A.3
- CCSS.MATH.PRACTICE.MP2

- Partitioning Circles
- Partitioning Rectangles

- CCSS.MATH.CONTENT.2.G.A.2
- CCSS.MATH.CONTENT.2.OA.C.4
- CCSS.MATH.PRACTICE.MP2
- CCSS.MATH.PRACTICE.MP5

- Partitioning Rectangles

**The Grade 2 lessons address the fourth critical area of focus in the geometry domain of the Common Core State Standards (CCSS):**

Students compose and decompose plane or solid figures (e.g., put two triangles together to make a quadrilateral) and build understanding of part-whole relationships as well as the properties of the original and composite shapes. As they combine shapes, they recognize them from different perspectives and orientations, describe their geometric attributes, and determine how they are alike and different, to develop the background for measurement and for initial understandings of properties such as congruence and symmetry (CCSS, 2010, p. 13).