In this unit, students will recognize defining attributes of 2D shapes and cubes, draw 2D shapes, and partition rectangles and circles. Students will build on their Grade 1 work with partitioning geometric shapes by partitioning shapes into thirds. Students will also discover that equal shares can have different shapes, a concept that is likely to be challenging for some students.
Key Concepts:
 Certain shapes (triangles, quadrilaterals, pentagons, hexagons, and cubes) are defined by their sides and angles. (Lesson 1)
 Shapes can be partitioned into equal parts; a whole can be divided into two halves, three thirds, or four quarters/fourths. (Lesson 5)
 Equal shares of identical wholes do not need to have the same shape. (Lesson 8)
Prior Knowledge Needed:
 Identify defining attributes of shapes (Grade 1, Unit 7, 1.G.A.1)
Units on the Horizon:
 Partition shapes into halves or fourths (Grade 1, Unit 17, 1.G.A.3)
 Describe a whole as 2 halves or 4 fourths (Grade 1, Unit 17, 1.G.A.3)
 Understanding unit fractions (Grade 3, Unit 4)
 Using fractions in measurement and data (Grade 3, Unit 5)
 Understanding equivalent fractions (Grade 3, Unit 10)
 Solving problems involving shapes (Grade 3, Unit 13)
Lessons

Lesson objective: Understand that angles and sides are defining attributes of shapes. Students bring prior knowledge of defining attributes from 1.G.A.1. This prior knowledge is extended to include angles as students sort shapes by defining attributes. ...

Lesson objective: Identify regular and irregular quadrilaterals. This lesson helps to build procedural skills with identifying quadrilaterals. Irregular shapes are used here because it supports students' understanding of defining attributes. This work d...

Lesson objective: Identify and draw shapes using defining attributes. This lesson helps to build procedural skills with identifying or drawing shapes given defining attributes. Irregular shapes are used here because it extends student understanding of d...

Lesson objective: Identify and name regular and irregular shapes. This lesson provides an opportunity for students to apply their knowledge and understanding of defining characteristics to a mathematical situation. Students are asked to design two sets ...

Lesson objective: Understand that shapes can be partitioned into three equal parts called thirds. Students bring prior knowledge of partitioning shapes into halves and fourths from 1.G.A.3. This prior knowledge is extended to include thirds as students ...

Lesson objective: Identify and name equal parts; partition shapes into equal parts. This lesson helps to build procedural skill with identifying and partitioning shapes. Regular shapes are used here because they provide students with multiple opportunit...

Lesson objective: Identify equal parts and combine them to create a whole shape. This lesson provides an opportunity for students to apply their knowledge and understanding of equal parts to a mathematical situation. Students are asked to work with a pa...

Lesson objective: Understand that equal shares can have a different shape or the same shape. Students bring prior knowledge of equal shares from 1.G.A.3. This prior knowledge is extended to equal shares that look different as students practice partition...

Lesson objective: Use folding and cutting to discover whether wholes can be partitioned into equal shares with different shapes. This lesson helps to build procedural skill with partitioning wholes into equal shares with different shapes. Rectangles are...

Lesson objective: Solve problems involving partitioning shapes. This lesson provides an opportunity for students to apply their knowledge and understanding of partitioning shapes to a reallife situation. Students are asked to create a flag out of a sha...