1. Operations and Equations Unit of Study: More Addition & Subtraction Strategies Global Concept Guide: 2 of 3

2. Content Development  Provide opportunities for students to use objects of equal weight and a number balance to model equations for sums and differences less than or equal to 20 using the numbers 0 to 20. Give students equations in a variety of forms that are true and false. Include equations that show the Identity Property, Commutative Property of Addition, and Associative Property of Addition. Students need not use formal terms for these properties.  13 = 13 Identity Property  8 + 5 = 5 + 8 Commutative Property for Addition  3 + 7 + 4 = 10 + 4 Associative Property for Addition  Common Misconception:  Many students think that the equals sign means that an operation must be performed on the numbers on the left and the result of this operation is written on the right. They think that the equal sign is like an arrow that means becomes and one number cannot be alone on the left.  Students often ignore the equal sign in equations that are written in a nontraditional way. For instance, students find the incorrect value for the unknown in the equation 9 = Δ - 5 by thinking 9 – 5 = 4.  It is important to provide equations with a single number on the left as in 18 = 10 + 8. Showing pairs of equations such as 11 = 7 + 4 and 7 + 4 = 11 gives students experiences with the meaning of the equal sign as is the same as and equations with one number to the left.

3. Day 1 Essential Question: How can you use addition to check subtraction?  Go Math Lesson 5.4, Listen and Draw p. 197 students solve in book. Discuss what operation is being used in each scenario. What is the relationship between the two scenarios and the two operations?  Use Change Unknown Problem Solving cards to model the scenarios. Students should use addition to help them check the subtraction.Change Unknown Problem Solving  Go Math On Your Own, p. 199 students independently complete #s 5 -11. By the end of Day 1, students should be able to use addition to check subtraction.

4. Day 2 Essential Question: How can you choose when to add and when to subtract to solve a problem?  Go Math Lesson 5.7, p. 209 – 212  Open with Listen and Draw being sure not to focus on key words, rather focus on direct modeling of the problem and discussing.  Share and Show, On Your Own and Problem Solving can be completed independently or as partners depending on student understanding. By the end of Day 2, students should be able to choose when to add or subtract to solve a problem.

5. Day 3 Essential Question: How can you use a balance to solve for an unknown number?  Building Conceptual Knowledge: Voyages Excursions Lesson: Balance MeBalance Me  It is important for students to clearly understand what the equal sign means. This lesson uses a pan balance to demonstrate how an equation should be “balanced” on both sides of the equal sign. The equal sign means “the same as.”  Provide opportunities for students to see the equal sign to the left of the expression as well as to the right of the expression.  Example: 7 = 5 + 2 and 5 + 2 = 7 By the end of Day 3, students should be able to use a balance to solve for unknown quantities in addition and subtraction problems.

6. Day 4 Essential Question: How can you decide if a number sentence is true or false?  Go Math Lesson 5.9 p. 217 – 220.  Listen and Draw p. 217 Students can build models to prove thinking before coloring in cards.  Share and Show p. 218 Students should select number sentences that are true and cross out sentences that are false. Interview students about how they know which to circle and which to cross out.  On Your Own p. 219 and Problem Solving p. 220 Encourage students to discuss what they could do to make the false sentences true.  Extend the Math TE p. 219 Students analyze given numbers and write number sentences that equal a given number. Then students organize number sentences into true or false piles. By the end of Day 4, students should be able to decide if a number sentences is true or false and provide rationale.

7. Day 5 Essential Question: What is the meaning of the equal sign and how do we use it in number sentences?  Dana Center Understanding the Equal SignUnderstanding the Equal Sign  This lesson focuses on the equal sign as meaning the “same as” regardless of context and determines if an equation is true or false.  Build expressions with linking cubes or snap cubes to determine equality.  Provide multiple opportunities for students to critique the reasoning of others as well as express their rationale for determining equality.  Know that in Part II there are multiple solutions possible. This is a great opportunity to explore how many number combinations can have the same sum. By the end of Day 5, students should be able to explain that the equal sign’s meaning is “the same as” and can accurately use the symbol in number sentences.

8. Enrich/Reteach/Intervention  Reteach/Intervention  Go Math Chapter 5: Add to Subtract Bingo on p. 184  Go Math Chapter 5: TE p. 185B Tier 1 and Tier 2 Interventions  Go Math Chapter 5: TE p. 217B Tier 1 and Tier 2 Interventions  True or False Equations True or False Equations  Enrich  Go Math Chapter 5: E36 Missing Numbers  Go Math Chapter 5: E42 Coach’s Choice  Go Math Chapter 5: E44 Shape Number Code

9. Literature for your Classroom Library