Building Adding & Subtracting Independence

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SWBAT set up and solve simple addition and subtraction problems to 10 by rolling dice, lining them up correctly, recording and solving the equations.

Big Idea

Kindergarteners need plenty of opportunities to use conceptual understandings that they have learned like subtraction begins with the larger number and addition is commutative.

Daily Calendar & Counting Review

10 minutes

As we do everyday, we completed our daily calendar which we do on the ActivBoard. If you don't have an ActivBoard or SmartBoard, use a standard wall calendar, but make sure you do one. Calendar time supports so many kindergarten standards.

After our calendar is complete, we practice counting to 20 and back, by 10's to 100 and by 1's to 100. Since this lesson is taught in the last quarter of the year when the kids are ready for more challenging lessons, we now incorporate counting by 5's to 100 to support learning in first grade.

We do our calendar on Starfall (this part is free, the extended site has a fee).

Next we count to 20 forward and back:

Counting by 10's (Hiking)

Let's Get Fit (Counting to 100)

The counting to and from 20 videos never change. They stay from the first week through the whole year. It is a very challenging skill for the kids to learn. I require participation and I make sure they are looking and pointing at the numbers as they say them. 

I use a variety of videos for the other skills (counting by 10's and 1's). This keeps the kids interested and engaged. The goal is to have all the kids counting independently by 10's, 1's and backwards from 20. This supports concepts that are taught in first grade and K.NBT.1, which focuses on a single ten and extra ones to make teen numbers.

Direct Instruction

10 minutes

I use the story 5 Little Ducks (one of their favorites) to think aloud about addition and subtraction. As I read the story, I think aloud the math that reflects addition and subtraction. For example, there were 4 little ducks so I think aloud about how there were 5 and one left (5 - 1) and also if there were 5 and now there is 4, how many ducks do I need to get 5? (Missing addend, which develops conceptual understanding and subitizing.)

Once I have read the story, we sing to two videos:

When you add with a pirate.

When you subtract with a pirate.

After we sing to our videos (we love them!) we discuss the difference between addition and subtraction. Then I demonstrate how the activity for the day is done.

I roll the sign dice, then the two number dice and set my problem up. If it is subtraction I stress that I must put the larger number first. If it is addition then it doesn't matter which one I put first because the numbers in addition are commutative.

After I properly set my equation up using the dice, I record my problem on a whiteboard and solve.

The students will work in pairs. The partners coach each other in structure and solving.

Guided Instruction

10 minutes

For guided instruction, I have the kids sit at the tables with their partners. I have my helper of the day help me pass out the materials. The kids are expected to be quiet and patient as the materials are passed out. They are also expected to keep their hands in their lap until I ask them to touch the tools.

Once all of the materials are passed out, I have the A partners go first. I guide them step by step. I also roam the room to help support and correct anyone who needs it. Partner A's are my high and medium-high achievers so they usually do well with activities once they see the demonstration and they follow step by step instructions well. Partner B's are expected to watch Partner A's actions to reinforce what they saw me demonstrate in the DI.

The step by steps:

Partner A goes first

1) Roll the sign dice and tell your partner what sign you rolled. Pause. Now tell them what it means (get more or take away).

2) Roll a number dice, state the number rolled to your partner

3) Roll the second number dice, state the number to your partner

4) Make the equation. If you have a subtraction sign, you must put the larger number first. Pause.

If you have an addition sign, you can put either number first.

Roam and assist with this for several rounds.

Partner B goes next.

I guide them for several rounds until it appears that they are able to do it with support of each other. I have had classes that require a full day or two of guided instruction before they can play on their own. That's okay! There is no benefit in rushing them.

The video shows me supporting a Partner B student. Notice Partner A jumps in to assist.

Independent Practice

15 minutes

Once they provide evidence that they are ready to take this activity on for themselves (this usually looks like restlessness or them moving ahead before you've given the instruction), allow them to play a round on their own while you carefully roam and monitor. Intervene when you see they are unable to coach each other, or when a partner doesn't engage when someone is struggling. Then remind the partner of his/her role while the other is playing his/her turn.

Allow them to do this activity as long as time allows. Since this is such a challenging concept that prepares them for first grade, there is not a level of mastery required. I do not give them an exit ticket. I spend more time in the closure focusing on the math and the thinking they had to do when the were playing.


10 minutes

Once we clean up our supplies, I have the kids come to the carpet one table at a time QUIETLY. After we are all gathered on the floor, I ask the kids to explain what they learned and how they knew what to do when they rolled each type of problem.

We end up recording our thoughts into three different flow charts:

1) How to play and decide which type of problem you're going to solve.

2) How to solve an addition problem.

3) How to solve a subtraction problem.

The flow charts come are handy for use in future discussions.