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NC Mathematics Standard:
Work with equal groups of objects to gain foundations for multiplication.
NC.2.OA.3 Determine whether a group of objects, within 20, has an odd or even number of members by:
· Pairing objects, then counting them by 2s.
· Determining whether objects can be placed into two equal groups.
· Writing an equation to express an even number as a sum of two equal addends.
Standards for Mathematical Practice:
1. Make sense of problems and persevere in solving them.
3. Construct viable arguments and critique the reasoning of others.
4. Model with mathematics.
7. Look for and make use of structure.
8. Look for and express regularity in repeated reasoning.
- I can identify a group of objects as being even or odd using different strategies.
- I can understand and explain why a group of objects is odd or even.
- Large number of Unifix cubes (or some type of manipulative students can grab) for each student.
- Hundred board per student
- Markers or chips in two different colors (crayons if using paper hundreds board)
- Smartboard of hundreds board (optional)
- Math journal to record and explain
- My Odd Day or My Even Day by Doris Fisher or another literature book about odd and even numbers
- Thinking: Students would need to be familiar with a hundred board and know how to group objects.
- Materials: Prepare large amounts of Unifix cubes or other manipulatives for each student.
- Have students come to the front of the room in groups such as everyone wearing glasses, or everyone with a brother, everyone with a birthday this month, etc. Ask each group to form partners. Each time record on a hundred board whether everyone has a partner or if there is someone left over. If there is a partner color the number on the hundreds board in green, (or use a green marker) if there is not a partner, color the number red on the hundreds board ( or use a red marker).
- After doing several of these examples with numbers from 1 to 20 ask students if they see a pattern in the structure of the numbers on the hundreds board. Have students write a prediction in their journals of what they think will happen when they work with larger numbers.
- When predictions are completed, students will grab a handful of cubes or other manipulatives and continue to record on the hundreds boards by coloring partner numbers green and no partner numbers red. They will repeat this several times.
- Look back at the predictions with students and discuss what happened. Ask students to write what they have learned in their journals. Chart ideas from student responses looking for the words “odd” and “even” to come out of their discussion. Focus this discussion on rules about which numbers are odd and which numbers are even and how we know.
- Close the lesson by reading My Odd Day or My Even Day by Doris Fisher. These books will help students deepen their understanding of odd and even.
Questions to Pose:
Discuss which group is odd/even.
How do I know if a number is odd or even?
What strategies can I use to determine if a number is odd or even?
What patterns do you see in the structure of the numbers on the hundreds board?
How does this structure relate to odd and even?
Students may not be able to partner up the manipulatives correctly.
Teacher would need to facilitate individual conversations with students that need help and model groups of two.
Students may not be able to generalize the pattern of the structure of number on the hundreds board.
These students may need the teacher to help them construct this understanding by asking additional questions and filling in more of their hundreds board.
This task only addresses the first part of the standard taught. The progression of the next lesson should lead into an understanding of writing an equation to express an even number as a sum of two equal addends.