Illuminations: Do It with Dominoes

Do It with Dominoes

Unit Overview

Lesson 1

Lesson 2

Lesson 3

Lesson 4

Lesson 5

Lesson 6

Exploring Adding with Sets

This lesson builds on the previous two lessons and encourages students to explore another model for addition, the set model. This model is similar to the counting model in the first lesson, because it is based on counting. Reading a related counting and addition book sets the stage for this lesson in which students write story problems, find sums using sets, and present results in the form of a table. In the discussion of the table, the students focus on the order property and the effects of adding 0.

Learning Objectives

Students will:

explore the results of adding sets
review the order (commutative) property
define and use the terms “addend” and “sum”
explore the effects of adding 0
construct a table showing addends and sums

Materials

The Hershey’s Kisses Addition Book (or another appropriate book)
Dominoes
Workmats, such as construction paper
Chart paper
Number of Spots Activity Sheet

Instructional Plan

To set the stage for this lesson, you may wish to read The Hershey’s Kisses Addition Book, or a similar book. Then ask the children to write an addition story problem that uses sets. Encourage them to share their problems and to put them in their portfolios.

Then provide groups of children with dominoes and a workmat. Tell them that they will consider the number of spots on each side of the domino as a set. Ask them to choose a domino and record the number of spots on each side as well as both sides combined. Next, tape up a large piece of chart paper that displays a recording table featuring columns that you have labeled “Number of Spots on the Left Side,” “Number of Spots on the Right Side,” and “Number of Spots in All.”

Number of Spots on the Left Side	Number of Spots on the Right Side	Number of Spots in All

Display a 5+4 domino and have the students suggest what will go in each column (e.g., 5, 4, 9). Then have them work in pairs to create new entries for the table. When they have identified the sum, help them enter their findings on the class chart. Allow the children time to make several entries, then call them together and review the terms “addend” and “sum.”

A partially completed (sample) chart is shown below.

Number of Spots on the Left Side	Number of Spots on the Right Side	Number of Spots in All
addend	addend	sum
5	4	9
3	5	8
0	6	6
2	2	4

Call on a volunteer to read one row of the chart. Then call on other volunteers to read the other rows. When several have been read, ask the children if they see any similarities among the entries. Repeat with other volunteers. If examples of the order property are not mentioned, prompt them to notice such entries. Also call attention to rows where at least one addend is zero. Encourage students to also notice rows in which the last column shows the same number.

Alternatively, students may record their domino information on the Number of Spots Activity Sheet.

Number of Spots Activity Sheet

Finally, ask the students to choose one of the rows from the chart and draw a picture (using dominoes or something personal to them) illustrating that number fact. They may wish to display these in the classroom or in a more public place.

For the example above, students would write 4 + 5 = 9.

Questions for Students

How many spots are on the left side of this domino? On the right? How many in all?

[Answers will depend upon the dominoes in question.]

Which sum that we listed was the greatest? What addends were used? Do you think we could get a larger sum with this set of dominoes? How?

[Answers will depend upon the dominoes used in the lesson.]

Suppose you had a domino with a “5” and a “0.” What would be the sum? How about a “0” and a “5?”

[5; 5.]

Look at this row. Does any other row have the same sum? The same two addends?

[Answers will depend upon the rows in question.]

Would you get the same thing if you had a “4” on the left and a “3” on the right as you would if the “3” were on the left and the “4” on the right? Can you show why?

[Yes; 4 + 3 = 7 and 3 + 4 = 7 also.]

Assessment Options

The suggested Questions for Students may assist you in understanding your students’ level of knowledge, but others may suggest themselves as you dialogue with your students.
You may find it helpful to add to your recordings on the Class Notes sheet that you began earlier in this unit. This data may be helpful as you plan strategies for regrouping students and for remediation or extension activities.

Teacher Reflection

Which students met all the objectives of this lesson? What extension activities are appropriate for these students?
Which students did not meet the objectives of this lesson? What misconceptions did they demonstrate?
Can most of the students justify the sum when one addend is “0?”
What parts of the lesson went smoothly? Which parts would you change the next time that you teach this lesson?

NCTM Standards and Expectations

Number & Operations Pre-K-2

Count with understanding and recognize "how many" in sets of objects.
Use a variety of methods and tools to compute, including objects, mental computation, estimation, paper and pencil, and calculators.
Develop fluency with basic number combinations for addition and subtraction.
Develop and use strategies for whole-number computations, with a focus on addition and subtraction.