1. Ways to Numbers Within 20
Unit of Study: More Addition & Subtraction Strategies
Global Concept Guide: 3 of 3

2. Content Development
It is important to help children understand that fluency means to be able to recall a fact quickly without having to count or to use other inefficient strategies.
Remember: we want children to understand the concept of addition and subtraction, then develop strategies to add and subtract, and finally develop fluency with the facts.
Since we are currently building a foundation for later work with all numbers and operations, students should make the connection that they can use the same strategies for the basic facts to 10 to work out facts to 20 and then with greater numbers in the future.
Sometimes students may be confused about how addition and subtraction facts can have the same sum or difference when they are not related.
Example: = 6 and 8 – 2 = 6, they are both ways to make 6 but the sentences are not related, the parts of the whole are different.

3. Day 1 Essential Question: How can making a model help solve a problem?
Go Math Lesson 5.1: Unlock the Problem p. 185
Begin by having students focus on the problem solving situations. Students will be using bar models and snap cubes to help them solve word problems that have missing addends or subtrahends (numbers that are subtracted). As students use the models (cubes and bar models), help them understand why their model works or doesn’t work. This discussion will help them develop fundamental problem solving skills.
Ask questions such as: What do the cubes represent?; How are the cubes and bar models similar?; How are they different?; How is you model like the problem?; How is it different?
Students can continue to work on p. 186 – 188—determine if work should be independent, partner, or small group. Select problems that fit student needs and will meet instructional goals for lesson.
By the end of Day 1, students should be able to accurately solve a problem using a model.

4. Day 2
Essential Question: How can you add and subtract in different ways to make the same number?
Feel free to use other outside resources to make this an exploration lesson. You may look to Go Math Lesson 5.8 to gather ideas, but focus on using number cards, number webs, and multiple representation posters, etc. to make numbers and build corresponding models to prove equality.
Discuss how students may have different ways to make the same number and have them justify their answers.
By the end of Day 2, students should be able to represent equivalent forms of numbers using sums and differences within 20.

5. Day 2 Continued…
Essential Question: How can you add and subtract in different ways to make the same number?
Focus on these ideas when modeling to develop students’ understanding of the thought process they are using when adding to check subtraction.

6. Day 3
Essential Question: How can addition and subtraction strategies help you find sums and differences?
Go Math Lesson 5.10 Share and Show p. 222
Teacher assigns small groups five problems to first solve independently in journals using strategies learned. Then groups should come together and share out the strategies used and compare.
Go Math Problem Solving p. 224
Students independently complete #s 44 – 47 as a check for understanding. Observe students as they work and question students about what strategy they used and why?
By the end of Day 3, students should be able to select appropriate strategies to add or subtract and justify their reasoning to others.

7. Enrich/Reteach/Intervention
Go Math Chapter 5: TE p. 213B Tier 2 Intervention
Go Math Chapter 5: R43
Go Math Chapter 5: TE p. 221B Tier 1 Intervention
Enrich
Go Math Chapter 5: TE p. 213B Enrich
Go Math Chapter 5: TE p. 221B Enrich

8. Literature for your Classroom
Grab-and-Go Kit Juggling
Click on book cover to locate literature resources.