Story Problems Subtraction

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Objective

SWBAT solve subtraction story problems by using drawings.

Big Idea

In this lesson, the students learn to draw pictures to match subtraction problems in order to form a solution. They learn to listen for actions in the story that indicate the use of subtraction in order to solve the problem.

Daily Calendar & Counting Review

15 minutes

Each day we begin our math block with an interactive online calendar followed by counting songs and videos.

Calendar Time:

We do calendar on Starfall every afternoon.  This website has free reading and math resources for primary teachers. It also has a  “more” option that requires paying a yearly fee. The calendar use is free. A detailed description of Daily Calendar math is included in the resources.

Counting with online sources: Today we did counting practice to reinforce the counting skills. We watched two to three number recognition 0-10 videos (one to two minutes each) because some of my students students were still struggling with identifying numbers correctly in random order. We watched"Shawn the Train" and counted objects with him to refresh our memories on how to count objects to ten and to reinforce one to one counting. Since we have started the second quarter of the school year, we added to today's counting practice: counting to 20 forward and backcounting by tens to 100 and counting to 100by ones to get a jump on our end of the year goals.

Direct Instruction

10 minutes

I read a subtraction story to my students such as 5 Little Monkeys or Ten Little Monsters. I think aloud the math that I read on each page (5-1, 4-1, 3-1, 2-1, 1-1). I use my fingers to model what I'm reading because kindergartners often need a concrete mental image of mathematical operations.

Next I load J.8 Subtraction word problems - numbers up to 9 from IXL Learning onto the ActivBoard to review what we know about subtraction story problems so far. I pull names from a name stick can to call students up to the board to click the answers.

I am solving the problems using my fingers to model each problem while I think aloud through each problem. They are only called up to have experience using the ActivBoard to submit the responses.

Kindergartners need to see operations repeatedly in order to take it on successfully on their own. The IXL free online program provides plenty of exposure to story problem and has a variety of levels.

Guided Practice

10 minutes

Once the kids have seen solving and answering story problems on the active board, I start to read the problems to the kids as they come up one at a time to solve the problems while the rest of the class tries to solve them in their own minds on the floor. We agree or disagree with each answer. The students help each other solve the problems, or I guide them through them. The expectation is that every student is participating in solving every problem in some way.

This guided practice encourages independence and the solidification of the steps in solving the problem. It also helps them to learn what key words or scenarios to listen for that tell us what actions to take to solve the problems.

I have a helper hand out the Beginning Subtraction Word Problems page and we work on it together. Each student has a pencil and a hard surface to write on (old small whiteboards). We are gathered on the rug. It sounds something like this:

Me: I read the problem to the class: 4 bees were flying about. 2 bees went off to make honey. How many bees were left?  I pull a name stick from the name stick can to choose my first student. How do we solve this?

Student: Do I start with 4?

Me: Let's ask our friends. What do you guys think? Should she start with 4?

Class: Yes

Me: Why should we start with 4? I give the chosen student a chance to answer first, then the class if necessary?

Student: Because because the story started with 4 bees?

Me (asking the rest of the class): Do you all agree?

Class: We agree (they show the thumbs up signal).

Me: We know the story started with 4 bees, so what do we do next?

Student: Take away 2?

Me: I ask the class if they agree. They do. I ask, Why are we taking away 2?

Student: Because that's how many went to make honey?

Me: So how many bees are left if there were 4 bees and two went to make honey? Can you show us on your fingers? If you have students hold their fingers in front of their chests, rather than up in the air, they won't be able to copy each other (as easily). 

Student: Holds up 4 fingers and puts 2 of them down. He has 2 left.

Me: Do you all agree?

Class: Yes (most of them are holding their thumb up).

Me: Then let's fill in the number sentence that goes with this story problem. I use my overhead projector to show them how to fill in the boxes.

I continue do this for three to four more problems, whatever time allows for. It goes faster with each subsequent problem.

Independent Practice

15 minutes

After we have had ample time to practice solving story problems, I encourage them to try it independently. I read each story and give them time to fill in the boxes on their own. I repeat all or some of the story problems as needed.

Just as the directions indicate, I ask them to use the pictures provided with each story to model the math. Then I ask the to write the corresponding number sentence and solve the problem and fill in the answer.

It is important that the kids get to a point where they can think through story problems and find the solutions on their own. Getting them to visualize what is happening in each story is usually the most challenging thing.

Exit Ticket

10 minutes

The exit ticket for this lesson is the completed independent practice page. I separate them into piles as I collect them. Since there are only four story problems, 0 incorrect is "meets" and those students continue with the current program.

1 incorrect is "Approaches" and is given 3-5 minutes with me in a one-on-one conference. This student usually has just missed counted something or wrote an incorrect numeral in one of the boxes.

2 or more incorrect answers is "Falls Far Below" and is placed in a small group (no more than three students) for further instruction and practice.

If the majority of my students are Falls Far Below, it is an indication that the lesson delivery was not suitable for them and that I need to reteach the concept in a different way.