Word problems with 3 Addends Part I

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SWBAT solve multi-step word problems by adding three numbers.

Big Idea

Following multi-step directions is a difficult task for first graders. This introductory lesson will teach them how to bring a word problem to life and help them visualize what needs to be done to solve by joining three numbers.

Rev Them Up

10 minutes

Let's talk and draw is a mini-lesson I designed to engage my students to work on their listening skills and solve math at the same time. First grade students need to be able to solve multi-step word problems and join three addends together, but, at their age, they tend to struggle with inattention. A talk and draw activity keeps their hands busy and minds focused. Drawing also helps make the abstract concrete, which is developmentally important for first graders. Since today's goal is to have them work on word problems with three addends, our discussion will be related to this topic. The addends will be sums of less than or equal to 20 and by the end of the entire lesson we will have covered several mathematical representations for each problem. (1.OA.A.2). I will pass out blank white paper and begin with:

Students, I heard that Serenity had 3 pencils, 2 books, and 4 erasers in her desk. That seems like a lot of things and I bet we could draw them. Go ahead and draw what she has in her desk. (They begin to draw, but I continue to talk and give ideas for descriptions to help bring their drawings to life.) What color do you think her pencils are? I bet they're yellow because we have yellow pencils in our supply can. I know she loves to read books about monkeys, do you think her 2 books might have monkeys on them? What kind of erasers do we have in our class? Oh, wow, your right, those big pink erasers, she has 4 of them. When you finish your drawing, put your hands on your head.

Now I will guide my students with a few questions;

How many pencils did you draw? (3) Go ahead and circle them and write a 3 under them.

How many books did you draw? (2) Circle them and write a 2 under them.

How many erasers did you draw? (4) Circle them and write a 4 under them.

What could we do to figure out how many things she had in her desk? (We could count them altogether.) Awesome, let's do that. What did she have in her desk? (9 things)

If this activity proved successful for your students to listen, draw, and answer the questions, then move on to the whole group interaction. If you feel that some students were lost and my benefit from more discussion, then create another verbal problem and walk them through it in the same manner.

Whole Group Interaction

5 minutes

In the Rev Them Up section, my students discovered drawing can assist them in solving a problem with three addends. In this section, I will help my students identify all the methods they can use to solve a three addend word problem. I will open up the discussion with:

Students you were helping me solve a word problem that added three different numbers together. What did you do to find out how many things were in Serenity's desk? 

I want them to identify the following steps:

  • we paid attention to the problem and the details.
  • we drew the amount of each item that you said.
  • we wrote the number for the amounts.
  • we counted how many there were altogether.

However, I want them to learn they can solve a word problem by doing more than just drawing. I want them to know they can solve with objects, drawings, and using symbols to create equations. (1.OA.A.2). I will be having my students use the Word Problem Work Mat to solve 3 problems for independent practice. I will have them work through a problem with me using the mat. This mat and the entire process will assist them in thinking abstractly and quantitatively (MP2) The mat will have them work abstractly by developing tally marks to join 3 addends and quantitatively by developing an addition equation to solve.

When they are solving the addition equation, I also encourage them to think about the fast facts we have practiced such as, facts that equal ten, doubles facts, zero the hero facts, and commutative property facts to add first. These strategies build addition fluency and give them a known starting point. I will open up the work mat on my Smart Board and pick a problem to solve from K-5 Math Resources. This will be the same resource I will use during independent practice.

Independent Practice

15 minutes

Print the Word Problem Work Mat and copy 3 for each student.

I will have my students practice solving word problem with 3 addends using the format supplied on the work mat worksheet. I will staple 3 work mats together. You can go here to access and print different word problems that supply 3 addends. I will cut apart the word problems and allow them to pick 3 problems to solve. I think the activity will interest them more if they get to solve problems that are related to their personal interests. This site supplies problems about puppies and kittens, cars, etc., and will appeal to both my girls and boys. They will glue a word problem on each work mat and then proceed to work through each one. I want them to draw a picture to represent what is in the problem. Write the symbols (numbers) to represent each problem, count using tally marks and finally write their answer in the answer box.

Check out my student completing work and another student beginning his problem. I will be walking around the room and observing if anyone needs assistance. There is reading involved in this lesson and I have some struggling readers. If I several students who are needing help, I will be gathering them together at our table to work as a small group. If I have a speedy finisher I will send him or her around to assist in reading only. All of my students are capable of attempting the math portion of this lesson and I do not want anyone thinking they can have friend do it for them.


4 minutes

I want to end our lesson and check to see who comprehended adding 3 numbers.

Students we are going to do one final lesson and for this one you can use your fingers as your objects to add with. I am curious how many hours we are in school each day. Listen to the problem, I will repeat it, do the adding on your fingers and then when I say "BAM!" show me your answer with your fingers.

We have been in school 2 hours. In 2 more hours it will be recess time. After 3 more hours we can go home. How many hours altogether?



Look for 7 fingers.