Sort by Attributes

Overview

This is lesson 7 of 30 in Building Mathematical Thinking. Students sort a small collection of familiar objects by one attribute, such as shape, color, size, or texture, then explain or demonstrate the sorting rule. The lesson builds on noticing and describing attributes and prepares students to count and compare categories.

Learning intentions

Students will be able to:

• Identify an attribute of an object, such as color, shape, or size.
• Sort objects into categories using one attribute at a time.
• Explain or show the rule used to sort a collection.
• Describe how the same objects can be sorted in more than one way.

Success criteria

• I can choose one attribute to sort by.
• I can place each object in the correct category.
• I can explain my sorting rule using words, pointing, or pictures.
• I can sort the same objects in a different way.

Curriculum links

• Measurement and Data — describe measurable attributes of objects, including size and other observable features.
• Measurement and Data — classify objects into given categories and count objects in each category.
• Geometry — describe objects in the environment using shape names and position language.
• Geometry — recognize and describe common shapes and their attributes.

Lesson structure (30 minutes)

1. 0–4 min · Hook and notice. Teacher displays a mixed collection of blocks, buttons, or classroom objects on the opening sorting question and asks, “What do you notice? How could we put these objects into groups?” Students quietly notice, then share one attribute with a partner or by pointing to a picture label.

2. 4–9 min · Model sorting. Teacher models sorting six objects by one attribute, thinking aloud: “I am sorting by color. These are red, and these are blue,” while using large visual category labels. Teacher briefly models a wrong placement and asks students to explain the correction. Students help place objects and repeat the sorting rule orally or with the frame, “I sorted by ___.”

3. 9–18 min · Partner sort. Teacher places students in five pairs and gives each pair a tray of 8–12 mixed objects, two or three category labels, and the attribute sorting recording sheet. Teacher directs pairs to choose or receive one attribute—color, shape, size, or texture—and checks that they use only that attribute. Students sort the objects, draw or mark the groups on the worksheet, and practice explaining their rule to their partner.

4. 18–24 min · Sort it another way. Teacher refers to the second-sort challenge slides and asks pairs to mix their objects and sort them using a different attribute. Teacher prompts, “What stayed the same? What changed?” Students create a second sort, compare it with the first, and show or tell the new rule.

5. 24–28 min · Share and check. Teacher selects two pairs to demonstrate different sorts and asks the class to identify the attribute and check whether every object belongs. Students use sentence starters such as “The rule is ___” and “This belongs because ___.” Students may answer orally, point to a category label, or demonstrate by moving an object.

6. 28–30 min · Exit sort. Teacher displays three objects and two visual category labels on the closing review slide. Students individually place or point to one object’s category and complete the oral prompt, “I sorted by ___ because ___.” Teacher records responses and previews that the class will count and compare the groups in a future lesson.

Resources

• the attribute sorting slide deck
• the attribute sorting recording sheet
• 5 trays or sorting mats
• 8–12 varied objects per pair: blocks, buttons, counters, toy shapes, or classroom items
• Large-print picture category labels for color, shape, size, and texture
• Two hoops, paper plates, or floor circles per pair
• Crayons, pencils, and dry-erase markers
• Optional timer and document camera

Assessment

• During modeling, ask individual students to identify the sorting attribute and predict where a new object belongs.
• During partner work, check whether students use one consistent attribute, place all objects in a category, and explain or demonstrate the rule.
• Use the exit sort to record whether each student can sort one object correctly and communicate the rule verbally, visually, or through action.

Differentiation

• Support students by using one attribute at a time, only two categories, modeled examples, and large visual labels with both pictures and words. Begin with clearly different colors or shapes before introducing size or texture.
• Provide sentence frames: “I sorted by ___,” “These are ___,” and “This goes here because ___.” Accept pointing, matching, gestures, or oral explanations instead of written responses.
• For dyslexia-friendly access, use large print, uncluttered worksheets, clear sans-serif lettering, high-contrast picture labels, minimal copying, and hands-on materials. Read all directions aloud and allow students to respond orally.
• For students needing additional support, work beside one pair, pre-sort one example, reduce the number of objects, or use a finished example as a visual reference. For older or advanced students, encourage them to justify why an object fits a category and identify an attribute that does not work for the collection.

Extension

• Sort the same objects in two different ways and draw or label both category arrangements.
• Create a “mystery rule” sort for a partner to solve, then explain why each object belongs in its group.
• Sort by one attribute, count each category, and tell which category has more or fewer objects.