Evens and Odds

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SWBAT identify numbers as even and odd, and write equations with two equal numbers to see that this results in an even number.

Big Idea

Students need to discover that adding any doubles results in an even number. This meets the Common Core Standard for using doubles to identify even and odd.

Warm Up

15 minutes

I begin today by handing each student a copy of the doubles rhyme that they created in a a previous lesson. We chant the rhyme together and I ask them to draw a quick picture next to each double to help them remember the answers.

I ask a student to come up and write a doubles fact on the board.

I ask the student to draw a picture to show the doubles fact  I ask if the numbers the student used were even or odd (i.e., if they used 5 + 5, are the 5s even or odd.)  How do they know if a number is odd or even? I take suggestions from students to help us understand how we might use pictures or objects to determine if a number is odd or even. 

I repeat the process until we have several even doubles and several odd doubles. I ask students to write in their notebooks what they notice about the kinds of answers (odd or even) that they find when they add doubles. 

I ask for several students to share what they noticed. 

I realize that they may not yet get the idea that all of the answers are even. We will work towards this during today's lesson.

I invite students to come to the rug to learn a new doubles game.

Playing the Game

15 minutes

I ask students if they can tell me what an even number is? I put some examples on the easel and ask if they are even or odd. 

I ask how I would be able to figure out if a number is even or odd. Some students know that 0,2,4,6,8 are the even digits. 

I bring out colored chips and 2 large plastic rings to sort into. We look at putting just 1 chip in one circle. Is there the same amount in each circle? Then we try 2,3,4,5,6,7,8,9. What do students notice. (At this point in second grade they should be able to verbalize which digits are even and odd.

Now I want them to transfer that understanding to larger numbers. 

I put the number 12 on the easel. Is it even or odd? I suggest that we put the chips in the circles and see if it is because the 1 is odd but the 2 is even. I have a child sort the 12 chips to see if they can put the same number in each circle, showing an even number, or a different amount showing an odd number. 

I repeat the process with the number 23. 

What do we notice about which digit helps us find if a number is odd or even?

Next I write a 3 digit number ending in 2, but with the 2 other digits odd (352). I ask the students if the number is even or odd and why they think so.

I repeat this with a number that has an odd number in the ones place (463). Again we decide if the number is even or odd. 

I ask students which digit I should look at to tell if a number is odd or even.

I tell students that again today we will be rolling a single die and doubling the answer. 

They will take a turn rolling an 8 sided die, doubling the number and putting a tally mark under even or odd.  They will be able to play for 5 minutes.

I hand out the tally sheets and the die to each set of 2 students and ask them to take turns.

At the end of the game I ask students to count up how many odds and evens they found. I tally up the answers and ask why we have no odds. 

At this point I hope students will begin to realize that when you double a number the answer is always even. 

I tell students that we will do a practice page with doubles and invite them to return to their desks.

Individual Practice

15 minutes

In order to meet the needs of the diverse learners in the classroom, I have created two different practice activities and pages.

I divide the class into two groups. 

The group that is able to work easily with larger numbers will be analyzing doubles data to see what happens when you keep doubling a number. They will predict how much the number will be after 1 week. (They will do this using pennies that they can trade in for dimes, and dollars.)

The other group will play the doubles +/- 1 game that they played in a previous lesson, but this time they will determine if the number that they get after doubling, and adding or subtracting one, is odd or even. They will tally as they did earlier in the lesson and try to figure out why now they are getting only odd numbers. 

The two groups will work independently on a practice page while I work with the activity group. They will switch after about 10 minutes of practice. 


10 minutes

Students have worked today to use doubles to think about odd and even numbers. They have also practiced some adding and subtracting of 2 digit numbers using doubles and partners of ten.

To see if they are meeting the Common Core expectation that they can identify an even number by adding two equal numbers, I ask them to write in their math journals the answer to the question, what two equal numbers can add up to 16. Can you write the number sentence to show the two equal numbers that equal 16.

I will use their responses as an informal assessment.