General Information
Benchmark Instructional Guide
Connecting Benchmarks/Horizontal Alignment
Terms from the K-12 Glossary
- Hexagon
- Rectangle
- Regular polygon
- Octagon
- Pentagon
- Triangle
- Square
- Polygon
Vertical Alignment
Previous Benchmarks
Next Benchmarks
Purpose and Instructional Strategies
The purpose of this benchmark is for students to work specifically with two-dimensional figures to categorize them based on their attributes.- Instruction includes a variety of examples and non-examples which lack defining attributes.
- Instruction includes the understanding that some figures may share the attributes of another figure, possibly creating subcategories. For example, squares form a subcategory of rectangles.
- Instruction is not limited to polygons.
Common Misconceptions or Errors
- Students may not realize figures can be categorized in more than one way.
- Students may have difficulty categorizing figures that are considered irregular.
Strategies to Support Tiered Instruction
- Teacher may refer to “Collect and Display” activity from 2.GR.1.1 and replicate for this benchmark activity.
- Teacher provides students with a collection of two-dimensional shapes, including triangles, rectangles, squares, pentagons, hexagons, and octagons as well as some non-examples, to do the following activities:
- Teacher, using only regular plane figures, asks students to sort them by size, shape or color. If needed, the teacher can explicitly teach that shapes can be sorted in different ways. Call attention to the words used during each sort to help students make connections between their informal language and the formal content vocabulary (see “Collect and Display” math language routine above).
- Teacher provides a set of plane shapes, including irregular polygons, and asks students to sort them any way they can but that they must use all the figures provided.
- Teacher asks, “How did you decide to sort them that way?” or “How did you know which shape belongs in this group?”, calling attention to the student language used and its connection to the formal content language.
Instructional Tasks
Instructional Task 1 (MTR.2.1)
Provide students with isometric dot paper. Read aloud and describe a two-dimensional figure by naming the attributes.- Part A. Draw the figures described. Once the figures are drawn, cut and place their figures under the appropriate provided categories in the table below. Some figures may fit in multiple categories, so encourage students to choose different categories to place their figures in, have students.
- Part B. Discuss why you chose the different categories. Help students understand that some figures may not fit into any categories during this task (e.g., figures with curved sides).

Instructional Items
Instructional Item 1
Tina builds the following figures and categorizes them both as hexagons. Is she correct? Explain why or why not.*The strategies, tasks and items included in the B1G-M are examples and should not be considered comprehensive.