1. Using Place Value to Add and Subtract Unit of Study: Two Digit Addition and Subtraction Global Concept Guide: 3 of 3

2. Content Development In this GCG, students will be exposed to modeling tens and ones in order to add and subtract. It is essential students model numbers with tens and ones. If students only experience two digit addition and subtraction with the standard algorithm, the students will lack understanding of the operations of addition and subtraction. The process of exchanging 10 ones into a ten needs to be a meaningful experience and students will need conceptual understanding for future concepts. Students will build this understanding of tens and ones with manipulatives (base 10 blocks) and transition into quick pictures. Students will use these strategies to add and subtract within 100. When adding and subtracting with place value, students should be exposed to problem-solving situations. (SMP 1) Many problems in Go Math are strictly computational, teachers can add a corresponding problem situation to increase the rigor of the task.

3. Day 1  On day 1, students will be exchanging ten ones into a ten. This understanding is essential for future lessons regarding place value and the operations of addition and subtraction. In addition of base 10 blocks, students can also use a tens frame to show the exchange of tens and ones.  Voyages Excursions Beans, Beans, Beans: Putting Into Action TE p. 98-99  Students will use base 10 blocks to model numbers spun on a spinner and exchange ones into tens.  Go Math Essentials: Lesson 8.6 Listen and Draw p. 337, On Your Own p. 339 #2-4, Problem Solving p. 340 #7-9  During this lesson, students will use base 10 blocks to make a ten to add and subtract. Students should be exposed to hands-on experiences and problem solving situations. The problems in Go Math are strictly computational, teachers can add a corresponding problem situation to increase the rigor of the task.

4. Day 2/3  Days 2 and 3 of this GCG will be continuous. Students will begin the place value model with base 10 blocks and transition into quick pictures. Again, students need a strong understanding of base 10 blocks and the connection with quick pictures. Quick pictures are sketches that students should complete in a short amount of time. The focus of quick pictures is to accurately and efficiently show place value to add and subtract.  Go Math Lesson 8.7 Essentials: Listen and Draw p. 341, On Your Own p. 343 #2-4, Problem Solving p. 344 #7-9, Extend the Activity p. 343  Provide students will multiple opportunities to show addition and subtraction with both base 10 blocks and quick pictures.  Click here for problem situations that relate to manipulatives and quick pictures.here

5. Day 4  On days 1-3, students have been able to make a ten and demonstrate place value with base 10 blocks and quick pictures. This lesson focuses on problem solving and students being able to understand how place value helps addition and subtraction.  Engage: Go Math: Math Journal p.348 TE: Draw a picture to show how to find 12 + 37. Extension: Write a problem situation to match this expression.  Go Math Lesson 8.8 Problem Solving: Addition Word Problems and P165

6. Day 5  This day allows students to use all of the strategies used to add and subtract. Students should be able to name different strategies and determine when it is appropriate to use a strategy.  Go Math p. 349 Listen and Draw: Provide students with the problem situation and allow them to select their strategy and solve. Provide opportunities for students to share strategies and explain their reasoning.  Go Math p. 352 Problem Solving

7. Reteach/Intervention  If students are still having difficulty with base ten blocks and quick pictures, students can explore these concepts with other tools, such as snap cubes, ten frames, etc…  Go Math Tier 1 and Tier 2 p. 337B  Students use snap cubes and ten frames to make a ten to add.  Go Math Tier 1 p. 341B  Students will use base ten blocks to model numbers and show the addition of these numbers with base 10 blocks.  Go Math R68: Problem Solving: Addition Word Problems  Students are presented with a problem situation and progress through each step of the problem solving process. The reteach page only provides one problem situation, but the process can be repeated with more problem situations.  Go Math Tier 1 p. 345B  Go Math Tier 1 p. 349B  Go Math Tier 2 p. 349B

8. Enrich  Go Math E67: Add and Match  Students will add tens and ones. They will also explain their reasoning for number three.  Go Math E68: What is the Problem?  Students will complete the addition sentence and write a matching problem situation. (SMP 2)  Go Math E 69: Use the Clue  Students will have to utilize clues to solve for problems involving more than one computation.