standard_description: Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.
problem_activity: Narrative
The purpose of this activity is to sort quadrilaterals by their attributes. By now students may be inclined to look for sides of equal lengths and for right angles. They may not look for parallel sides (and are not expected to know the term “parallel”), but may notice that some quadrilaterals have pairs of sides that are oriented in the same direction (MP7). Encourage students to describe such observations in their own words.
The quadrilateral cards from this activity will be used in the next lesson and in centers.
Required Materials
Materials to Gather
Bags or envelopes
Materials to Copy
Quadrilateral Cards Grade 3
Required Preparation
Create a set of cards from the blackline master for each group of 2 or 4.
Bags or envelopes can be used to store sets of cards from this activity for use in the next lesson.
Launch
Groups of 2 or 4
Distribute one set of pre-cut cards to each group of students.
“What do you notice about the shapes on this set of cards?” (There are 20 shapes. All the shapes are quadrilaterals. Some have right angles and some don’t.)
1 minute: quiet think time
Activity
“Just like the last activity, sort cards into categories that you and your partner choose.”
8 minutes: partner work time
Monitor for different attributes that students use to sort the shapes.
Student Facing
Sort the quadrilaterals into categories. Record your categories and be prepared to explain how you sorted the shapes.
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Student Response
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Activity Synthesis
“Display your sorted cards so that others can see them.”
“Visit another group’s cards and see if you can figure out how they sorted their quadrilaterals. Be prepared to share your reasoning.”
2–3 minutes: Students visit other groups’ displays.
Invite each group to share how the cards were sorted and their reasoning. Record and display the attributes students use to categorize the quadrilaterals.
Attend to the language that students use to describe the categories and shapes, giving them opportunities to describe the shapes more precisely.
Highlight the use of terms like “equal sides” and “right angles.”


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