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Reason with shapes and their attributes

Second Grade Perspective

Students describe and analyze shapes by examining their sides and angles. Students investigate, describe, and reason about decomposing and combining shapes to make other shapes. Through building, drawing, and analyzing two- and three-dimensional shapes, students develop a foundation for understanding area, volume, congruence, similarity, and symmetry in later grades.

Scaffolded Ideas

 - Students need an understanding of how shapes are described by specific attributes before being able to identify particular shapes.
 - Students need to know the meaning of the words half, thirds, fourths and quarters and the phrases half of, third of, fourth of, and quarter of before they learn to partition circles and rectangles into two, three, or four equal shares.
 - Dividing shapes into equal shares is related to a basic understanding of fractions.

Questions to focus instruction:

 - What is the definition of the following shapes: triangle, quadrilateral, pentagon, hexagon, and cube?
 - How do students demonstrate an understanding of dividing shapes into equal shares?

Associated Standards:

2.G.1. - Recognize and draw shapes having specified attributes, such as a given number of angles or a given number of equal faces. Identify triangles, quadrilaterals, pentagons, hexagons, and cubes.
2.G.2. - Partition a rectangle into rows and columns of same-size squares and count to find the total number of them.
2.G.3. - Partition circles and rectangles into two, three, or four equal shares, describe the shares using the words halves, thirds, half of, a third of, etc., and describe the whole as two halves, three thirds, four fourths. Recognize that equal shares of identical wholes need not have the same shape.