South Carolina ETV

South Carolina ETV
1101 George Rogers Boulevard
Columbia, SC 29201-4761
Phone: 803-737-3545

Let's Trade (Grade 2)

Master Teacher

Shirley Peeples

Time Allotment

One 55-minute class session

Overview

This lesson focuses on adding two-digit numbers and the regrouping process. Students will identify when the regrouping process is necessary and make appropriate "trades" to complete an addition problem.

Subject Matter

Mathematics

South Carolina Standards

Visit the South Carolina Department of Education for the South Carolina Mathematics Standards.

Mathematics—Grade 2

II. Numerical and Algebraic concepts and Operations

A. Use concrete models to develop an under- standing of the concepts of addition . . . with whole numbers.

B. Use models to allow students to construct their own algorithms for addition . . . of whole numbers.

*The student will solve addition and subtraction problems using data from simple charts and picture graphs. Problems will require a one-step solution.

III. Patterns, Relationships, and Functions

C. Represent, discuss, and describe mathematical relationships and make generalizations based on observed patterns and relationships.

*The student will recognize, describe, and extend patterns of numbers and number combinations using tools, such as hundreds charts and calendars.

Learning Objectives

Students will be able to:

correctly add 2 two-digit numbers with regrouping, resulting in a sum in the hundreds place value.

Materials

Per group of 2-3 students:

Unifix Cubes (122 individual cubes and one 100-block)
Activity Sheet 1: Place Value Mat
Activity Sheet 2: Addition Skill Sheet
Activity Sheet 2 Cont'd: Addition Skill Sheet

Media Components

Video

Mathica's Mathshop 2, Lesson 2: A Merry Band. Mathica is asked by the king to hire the three top musical acts for his daughter's party. To help her make this decision, Mathica uses charts, graphs, and Unifix cubes to show the hands-on process of addition with regrouping.

Prep for Teachers

Preview the video Mathica's Mathshop. Note the Focus for Media Interaction points in the Learning Activities section.
Place Unifix cubes—122 individual cubes and one 100-block—in a gallon-sized Ziplock bag for each group. (This task can be accomplished prior to the lesson by student helpers.)
Enlarge and copy the Place Value Mat (Activity Sheet 1) for each group of students.

Introductory Activity: Setting the Stage

Step 1

Establishing a Knowledge Base. Pass out prepackaged bags of Unifix cubes and mats to the students. Allow students time to explore the cubes. Then ask the students to identify the hundreds, tens, and ones place on the Place Value Mat. Ask the students to listen as you call out a practice number and to make that number on their mat using their cubes. Give several examples to establish understanding.

(Example: 58 = 5 bundles of ten and 8 ones; 117 = one block of 100, 1 bundle of ten, and 7 ones, etc...)

Step 2

Establishing a Personal Connection with Math. Ask students to tell why it is important to be able to add large numbers together. Listen for real-life examples such as: to add money amounts when shopping, to be able to figure out what is more of something, to compare more than one piece of information, etc . . . .

Step 3

Introduction of Video. Tell the students that you want them to connect 10 Unifix cubes together to make a "magic wand" because they are going to visit an elf in Mathland who needs their "magical" help to solve a big problem for the king. Tell them that they will be learning how to add 2 two-digit numbers together to help a musician solve his dilemma.

Learning Activities

Step 1

Focus for Media Interaction: Ask students to listen for the names of the three top-selling acts and to raise their "magic wands" when they have identified them.

START "The Merry Band" from the beginning and STOP after Mathica identifies the four musical acts and their totals on the chart and says, "No way the king is going to hire an act with sales lower than everybody else."

Ask the students to identify the three top musical acts from the chart. (Answer: Bremen Town Musicians, The Fiddlers Three, and the Pied Piper) Then ask the students what information is missing from the chart. Students should identify Robin Hood's missing weekly sales total. Ask them why this information is important and have them predict what Mathica could do to get this information to complete the chart.

Step 2

Focus for Media Interaction: Ask students to raise their magic wands when they hear what Robin's missing sales are for the week.

RESUME tape. Watch for wands to rise when the answer of 64 is revealed. PAUSE the tape when Math Magician says, "What are Robin's total record sales?"

Step 3

Focus for Media Interaction: Tell students they will now see how Mathica figures out how to add together Robin's sales from the chart. Instruct students that they will work in groups and place Unifix cubes on their mats as Mathica shows them how on her mat in the video.

Students place Unifix cubes on their Place Value Mats as Mathica does in the video. PAUSE video as needed to allow students time to place corresponding cubes on their mats and to check for accuracy. When Mathica and the students have placed 58 and 64 cubes on their mats, and Mathica says, "8+4 is 12," PAUSE the video and ask students if there are any groups of 10 that could be moved over to the tens place. Students should identify how they can connect 10 Unifix cubes from the ones place together to make a group of ten and to move the group of 10 to the tens place on the Place Value Mat leaving 2 ones remaining in the ones place. RESUME video until Mathica has regrouped the ones column into the tens column then PAUSE.

Step 4

Focus for Media Interaction: Tell students to watch what Mathica does to the tens in the tens column and to wave their magic wands when they know what to do with their tens on their Place Value Mat.

CONTINUE video until Mathica says, "That's 12 tens." PAUSE video. Ask students to show what they would do with the 12 groups of ten. Check for predictions then CONTINUE video until Mathica has regrouped the 12 groups of ten into one group of a hundred and 2 tens. PAUSE tape and check student mats for accuracy.

Step 5

Focus for Media Interaction: Tell students that they will now find out how Robin's total record sales compared with the other acts. Tell them to wave their magic wands when they can predict the outcome.

START the video. Students should wave their magic wands when they can predict whether Robin will play for the King or not. STOP the video when Mathica says, "Since you and the Merry Band are the next top selling act, you can take their place."

Culminating Activity

Review the addition with regrouping format using Unifix cubes and Place Value Mats until students seem confident with the regrouping process. Other practice examples could be: 48+13, 29+81, etc...

Assessment

As a final assessment, give the students a copy of the Addition Skill Sheet (Activity Sheet 2) to complete. For students finishing this assignment ahead of time, tell them to turn their papers over and draw the sum of their age plus 98 in Unifix cube form.

Cross-Curricular Extensions

Writing: Have students write addition story problems using 2-digit numbers. Next, have them trade these stories with their friends and challenge their friends to find the solutions.

Literature Links: A Fair Bear Share: Level 2: Regrouping by Stuart J. Murphy, Harper Collins Publishers, Dec. 1997.

Science: Have the students research, compare and add the weights of large animals. Have students show their information on graphs or charts, and present the results to the class.

Math: Generate a class store using ads from a newspaper or real-life items for the students to buy. Be sure items cost two-digit amounts and that they buy at least two items so that they will have to add the items together to figure out how much they have spent.

Social Studies: Have students investigate how far they would travel using two destinations. (Example: from Ridgeland to Charleston is 75 miles and from Ridgeland to Columbia is 120 miles. What is the sum of the two destinations?) Be sure to use your map Web sites for this one!

Technology: Explore the following Web sites:

A+ Math. This Web site provides a flashcard-type format for student practice, along with games and worksheets.

Black Dog. This Web site provides an addition quiz where you match each number sentence to its sum. You can also play the "Beat the Clock" addition game.

Internet Learning Network. This Web site takes you on a "math safari" to discover math sums.

FunBrain.com. Under Top Games, click Math Baseball. Take a swing at math problems with this fun and challenging combination of baseball and math.

Community Connections

Invite a banker or business person to talk about the importance of knowing how to add large digit numbers and how this is used in their day-to-day routine.