Addition and Subtraction to One Million Unit of Study: Place Value, Addition and Subtraction to One Million Global Concept Guide: 3 of 3
Content Development While subtracting using the standard algorithm, students must carefully align the digits according to place value. Students must also recognize if the digit being subtracted is greater than the digit it is being subtracted from, they must regroup in order to subtract. Previous work with renaming numbers helps students understand that 3 tens 1 one can be renamed as 2 tens 11 ones. Students continue to use estimation to check the reasonableness of their answers. Since addition and subtraction are inverse operations, students can also use addition to check their answer to a subtraction problem. - Go Math TE 31A
Content Development - Go Math TE 35A
Refer to the Enrich/Reteach/Intervention slide at the end of this PowerPoint for ideas to differentiate instruction throughout this GCG as needed.
Day 1 • Prior to Day 1’s Lesson, give the Gaming Gurus performance task. Use the results of the performance task to make instructional decisions, and make connections to future content to continue review as needed. This performance task should not exceed 30 minutes. • EQ: What strategies can you use to add and subtract large numbers? • On Day 1, students are solving problems using the “choose an operation” problem solving strategy. Teachers need to provide real world problems using both addition and subtraction scenarios. Discussion needs to be facilitated about why students chose the operation they did. Pinch cards with addition or subtraction symbols would be a good resource to use in groups or with partners. Utilize a variety of problems from Go Math Lesson 1.6, 1.7 and 1.8 as referenced in the GCG. Use resources referenced on the differentiated instruction slide as needed on Days 1-3. • Teachers also need to facilitate discussion of strategies to determine reasonableness of the answer by using estimation and/or inverse operations. It is important to discuss how estimation is a tool to be used prior to solving. Compare and contrast different estimation strategies/tools, including but not limited to: number lines, benchmarks, and place value. • Students should be introduced to the “bar model” as a tool to model and solve addition and subtraction of larger numbers. Utilize problems from Go Math Lesson 1.8 as a resource and TE page 35A for more information about the bar model strategy. • Evidence of Learning: • Pose problem #8 on Go Math SE p. 38.
Day 2 • EQ: How do you know when to regroup when adding and subtracting large numbers? • On Day 2, students are using their understanding of place value and renaming numbers in order to add and subtract with regrouping. Based on observations from Day 1, select addition or subtraction problems to focus on. Utilize selected problems from Go Math Lessons 1.6, 1.7 and 1.8. • Students should use their understanding of representing numbers flexibly, knowing that 3 tens is the same as 30 ones etc, while solving for sums and differences of larger numbers. • Continue use of “place value” language as students discuss strategies used to add or subtract. • Have students continue to estimate before actually solving and use inverse operations to check reasonableness of solutions. • Evidence of Learning • Pose the addends 506,211 and 424,809. Have students create an addition story problem in their journal.
Day 3 • EQ: How do you use your knowledge of place value to add and subtract large numbers? • By the end of Day 3, students will be able to use place value language to explain why and how they used addition or subtraction to solve problems. • To engage students, pose the What’s the Error Problem on Go Math SE p. 34. Have students discuss what the error is. Discuss the importance of lining up the place values before adding and subtracting. Utilize problems from Go Math Lessons 1.6, 1.7 and 1.8 based on student needs. • Evidence of Learning: • Pose the numbers 506,211 and 424,809. Have students write a story that can be solved by finding the difference between the two numbers.
Enrich/Reteach/Intervention • Reteach • Response to Intervention Tiered Activities – 4th Grade Go Math TE 27B, 31B, 35B • Go Math ReteachR6&R8 • Core • Grab & Go Activity Ask Me About Area– Students will compare areas of different states. • Grab & Go Activity Tile Tabulations– Students will create different six digit numbers to estimate, add and subtract. • Take a Seat– Students will use a table about basketball seating capacity to solve real world problems involving addition and subtraction. • Enrich • 3-Foot Path – Students will determine a path of addends. • Take a Seat– Students will use a table about basketball seating capacity to solve real world problems involving addition and subtraction. • Pose an addition/subtraction number sentence for students to create real-world problems.