Problem Solving: Using Objects

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SWBAT solve addition problems using objects.

Big Idea

Some problems can be solved by using objects. Students can use these objects to act out problems.

Rev Them Up

6 minutes

This lesson will have my students solving addition using different strategies (1.OA.A.1). I want them to identify that a number is made up of subsets of smaller numbers, and this lesson will allow them to identify these subsets. It will also help them practice a valuable addition strategy: using objects to act out the problem.

I gather students at a spot in my room with a pocket chart so I can display six cards from a deck. It does not matter if you use hearts, diamonds, spades, or clubs.  Select a 2, 3, 4, 5, 6, 7, 8, and 9.  Have the students count the card identifiers with you to show them the objects match the number on the card. I want to make sure they see the connection between the numbers and the objects because the objects will be used to count and solve our problem. Now it's game time!

You will select four cards that two out of three will equal the fourth card. For example: I picked a 3, 4, 6, and 9.  I placed them in the pocket with the 3, 4, and 6 next to each other and the 9 scooted over about 5 inches.  I told them I wanted to build the 9, but only needed two cards from the 3, 4, and 6. What would I need to use to add together to build a 9?

This activity helps them see addition can occur by joining numbers together. Students can use any strategy that that assist them in finding the correct answer. I will have some unifix cubes available along with whiteboards and markers. I expect to see strategies such as:

  • using manipulatives to test hypothesis
  • drawing a picture
  • starting at a number and counting up by another number
  • selecting numbers for a known addition fact

My most important piece of advice is when you ask a student to share their answer is to always follow it with "why?" or "how did you get your answer?" You want them to share their critical thinking ideas and test ideas to determine outcomes and make connections between numbers. It is important to have them share their knowledge to help them become conscious of what they know. This will help them persevere and continue to take risk while solving (MP1).

I did it again three more times building a 7, a 5, and a 4. Check out the videos: making 7 and making 9.

Whole Group Interaction

15 minutes

Have the kids work with a partner.  I like to pair students who are solid with their number sense and addition facts with students who still need help (i.e. heterogeneous grouping).  This activity is gong to build on the Rev Them Up activity and give them more opportunities to join numbers together and act out addition problems using objects, and having a higher partner will help my lower students engage more fully in the task.

On the board, write and read aloud: Tom has 5 stickers.  He wants to put them on two different pieces of paper in his sticker collection.  Show me how he can put the stickers on the pages.

Pass out two small pieces of paper and 5 counters to each set of partners.

Walk around an observe how the students divided the 5 counters.  Go to the board and ask each set of partners to tell you what they did and make a list on the board, for example:

  • For 1 and 4, I would write 1+4
  • For 2 and 3, I would write 2+3

Your goal is to show them all the combinations the class came up with and discuss any missing combinations. You will also want to point out places where the Commutative Property comes into play to connect back to the previous lesson on this property.

Independent Practice

10 minutes

The solving with objects worksheet matches what we did in the Rev Them Up activity. Students will pick what card numbers will equal a particular number.  A great option to increase engagement and students' ability to interact with the manipulatives would be to provide students with their own set of cards from a class set if you have one to use as they go through the problems.

Check out the video of a student picking numbers for building 5

Also, I should note that I had one student who needed extra assistance completing the assignment.  She is at the beginning stages of developing number sense and one-to-one correspondence. Watch the video of me scaffolding her to the answer.


5 minutes

I will pass out one 3x5 index card to each student and ask the following question:

I have 8 things in my pencil case. Some of them are pencils and some of them are markers. Draw a picture and show me how many of each item I could have in my case.

I will collect their cards as they line up for our restroom break.