Decomposing 4

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Objective

SWBAT use 2-color counters to show different combinations for four.

Big Idea

We develop a procedure to systematically find ways to make four.

Attention Grabber/Introduction

10 minutes

I choose 4 boys to stand in front of the class in the meeting spot.  “How many kindergartners do we have here?” I ask.

“4”!  Students say.

“How many boys?  How many girls?” I ask.

4 boys,” they say.  I press on.  “How many girls?”

“0.” 

So “4 and 0 is 4,” I say, and take a picture.

I ask the boys on the right side to have a seat, and I fill in that spot with a girl.  “Now how many!?” I ask.

“3 and 1,” they say.  I repeat to clarify, “So 3 boys and 1 girl is… 1, 2, 3, 4.  Yep!”

Next, I have the next boy on the right side go sit down.  Another girl is selected to fill that spot, and I articulate that we have to keep 4 kindergartners up there.

We talk about the combination, 2 and 2.

Next, we ask the next furthest boy to sit down, and we replace that spot with a girl.

Finally, the line that was all boys, is now all girls?!  Do we still have 4?  But is it the same?

Well, just like groups of kindergartners, I continue, we can show 4 In different ways!

Guided Practice

20 minutes

We get our Decomposing 4 pages and begin with 4 red on top.  I “do” this activity on the big screen  with the students so there’s plenty of support.  We systematically flip the counter on the end over each time, so that by the bottom of the page, all the counters are yellow!

We make the little marks to know exactly what we’re supposed to color, so we don’t accidentally color the wrong circles.  After each progression in our system, we write numbers to show what we illustrate.

At the end, we have created all of the combinations to make four.

Closing

5 minutes

When we are finished with our combinations, I ask the students for feedback.  They like the part where the kids showed 4.  They like flipping the counters, they say. 

I ask if it’s getting easier, and even though the numbers are getting larger, the kiddos say “Yes!”