# Try, Check, Revise

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## Objective

SWBAT use the strategy try, check, and revise to solve real-world problems.

#### Big Idea

When you come up with an answer, you need to check it. If it is not corerct, go back and revise to find the correct answer.

## Opener

5 minutes

In today's lesson, the students evaluate their responses to real-world problems by using the Try, Check, Revise strategy.  This aligns with  4.OA.A3 because the students solve word problems posed with whole numbers and having whole-number answers with the four operations.  Also, this lesson aligns with 4.OA.B4 because the students are required to determine whether a given whole number in the range 1–100 is a multiple of a given one-digit number. This lesson is very important because too many students turn in papers with careless mistakes.  This concept will teach the students to ensure that their answers are correct before moving to the next problem.

To get the students started and excited about the lesson, I start by telling the students that I know a way that they can always make sure their answer is correct.  Of course I knew that they would want to know "how."   I ask the students to tell me "how" they think this can be done.  I allow them to think about it for a minute or two, then share with their elbow neighbor.  I take a few responses from the students.  Student responses:  1) You can use a calculator, and 2) you can look over your work before you turn it in.  Then I share with the students that today we will learn a new strategy called:  Try, Check, Revise.

## Whole Class Discussion

10 minutes

To begin the whole class discussion, I call the students to the carpet.  I like for my students to be near because it gives the classroom a community feel.  On the Smart board, I have a power point ready that explains the Try, Check, Revise strategy.  We begin the lesson with a problem. In this problem, the students solve word problems posed with whole numbers and having whole-number answers with the four operations (4.OA.A3).

Problem:

Ken wants to buy birthday gifts for his twin brothers.  Ken has \$27.00 to spend.  He wants to buy them the same item.  What can Ken buy for his brothers?

 Item Price (each) CD \$13.78 Shades \$13.50 Hat \$14.50

I give the students a few minutes to read and think about the problem.  I ask, "What is this problem asking us to do?"  Student response:  To find out what Ken can buy his two brothers.  "How do you think we need to solve this problem?"  I give the students a few minutes to think about the question.  Student response:  We can add to see which one Ken can get. I let the student know that he is correct.  I then explain and model the try, check, revise strategy to the students.

The first step of this strategy is to try.

Try:  Choose an item and add the cost.

CD:  13.78 + 13.78=

The second step is to check.

Ken only has \$27.00.  Is the total for the CD \$27.00 or less? Let's find out.

\$13.78 + \$13.78= \$27.56

I ask, "Will Ken be able to buy two CDs for his brothers?"  Student response:  No.  "You're correct, because the cost of 2 CDs is more than \$27.00."

The third step is to revise.

Because Ken would go over \$27.00, we need to try another item.

\$13.50 + \$13.50= \$27.00

I ask, "Will Ken be able to buy 2 pairs of shades for his twin brothers?"  Student response:  Yes.

I let the students know that Ken can buy 2 pairs of shades for his twin brothers because it did not go over \$27.00.

Before we begin our group activity, I let the students know that this is just one example of using Try, Check, Revise.  I let them know that this strategy can be used for any skill or any topic.  I tell them that they will see this in their group activity.

## Group or Partner Activity

20 minutes

During this group activity, the students work in pairs.  Each pair has a copy of the Group Activity Try Check Revise.  The students must work together to find the number that meets all the criteria. The students are required to determine whether a given whole number in the range 1–100 is a multiple of a given one-digit number. (4.OA.B4). The students are guided to the conceptual understanding through questioning by their classmates, as well as by me.  The students communicate with each other and agree upon the answer to the problem.  This takes discussion, critiquing, and justifying of answers by both students (MP3).  As the pairs discuss the problem, they must be precise in their communication within their groups using the appropriate math terminology for this skill (MP6).  As I walk around, I am listening for the students to use "talk" that will lead to the answer. I am holding the students accountable for their own learning.

As they work, I monitor and assess their progression of understanding through questioning.  It must be evident that they are using the try, check, revise strategy on this problem.  Some of the questions that I ask:

1.  What is the probem asking you to find?

2. Does your number meet ALL of the criteria? If not, what must you do?

3.  What operation do you use for finding a sum?

As I walked around the classroom, I heard the students communicate with each other about the assignment.  As I walked past one group, I heard a student say, "It has to be an odd number."  This lets me know that the student is paying attention to what the problem is asking her.  One group struggled with the problem.  To help guide the students to the answer, I questioned the students.  I asked questions, such as, "What does the problem ask you to do? What can you tell me about an odd number?  Describe a multiple of 5."  For each question I asked, the students had to refer to the problem to find the choices that were odd or ended with a 0 or 5.  These types of questions helped this pair of students find the answer.   I always tell my students that they must justify their answer by referring back to the problem.

Any groups that finish the assignment early, can go to the computer to practice the skill at the following site until we are ready for the whole group sharing.

## Closure

15 minutes

To close the lesson, I have a pair share their answers.  This gives those students who still do not understand another opportunity to learn it.  I like to use my document camera to show the students' work during this time.  Some students do not understand what is being said, but understand clearly when the work is put up for them to see.

I feel that by closing each of my lessons by having students share their work is very important to the success of the lesson.  Students need to see good work samples, as well as work that may have incorrect information.

Before class ends, I have the students write to explain how they solved the problem using the Try, Check, Revise strategy. This enables me to see how well the individual student understood the strategy.  I collect their papers as they leave the classroom.  From their paragraphs, I identify students that do not understand the concept to give them extra guided practice at the beginning of class the next day.