Global Concept Guides: Addition and Subtraction Strategies, Applying Addition and Subtraction Strategies
Prior Learning:MACC.1.OA.6
Progressions Document Link
Sample Show What You Know Task:You could use data collected from FASTT Math reports to evaluate student fact fluencyor you could give the students a timed fact fluency sheet to measure fluency.
Common Core State Standards for Mathematical Content :
Add and subtract within 20.
MACC.2.OA.2.2-Fluently add and subtract within 20 using mental strategies. By end of grade 2, know from memory all sums of two one-digit numbers.
Use place value understanding and properties of operations to add and subtract.
MACC.2.NBT.2.5 Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction. / Comments:
Notes on Assessment:
There is no Go Math assessment that correlates to this GCG.
See common performance task link below.
Unpacking the Standards for this Unit:
Research indicated that teachers can best support students’ memory of the sums of two, one-digit numbers through varied experiences including making a ten, breaking numbers apart, and working on mental strategies. These strategies replace the use of repetitive timed tests in which students try to memorize operations as if there were no relationship among the various facts. When teachers teach facts for automaticity, rather than memorization, they encourage students to think about the relationships among the facts. (FosnotDolk, 2001)
Common Performance Task with Rubric for this Unit:
Baked Cookies-Students will solve addition and subtraction problems using an open number line, plave value model, and a strategy of their choice.
Click here for the performance task and rubric.
Future learning:
Students will use fact fluency in grades 3 & 4. By the end of grade 3 students use a range of algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction to fluently add and subtract within 1000. By the end of grad 4 students are expected to fluently add and subtract multi-digit whole numbers using the standard algorithm.
2nd / Global Concept 1 of 2 for this Unit of Study:Addition and Subtraction Strategies
The purpose of this GCG is to review previous taught strategies to add and subtract fluently and build the students capacity to do so with automaticity. / Projected Time Allotment:5 days
Sample Essential Questions:
Day 1: How does understandingan open number line help you add and subtract multi digit numbers?
Day 2:How does understanding fact families help you build addition and subtraction fluency?
Day 3/4:How can understanding place value help you add and subtract fluently?
Day 5: How can using a part-part-whole mat help you work through problems?
Instructional Resources
Manipulatives:
- Countersto fill in the ten frame.
- Base Ten Blocks to build models of addition and subtraction scenarios.
- Open number lineas a tool for addition and subtraction.
- Missing Operations Worksheet-Students have to determine what the correct missing operation is.
- Fact Family Housesto build students understanding of fact families and their relationship.
- Part-Part-Whole Mat to represent addition and subtraction scenarios.
- Part-Part-Whole Questionsto use along with the part-part-whole mat.
- Base Ten Virtual Manipulative – virtual manipulative
Sample HOT Questions: Use these to facilitate student discussions. (SMP 1,3)
- Will any three numbers create a fact family?
- Is there any math problems where using place value would not be a good strategy?
- Can you use your knowledge of a ten frame to solve any addition and subtraction sentence?
- How does an understanding of fact families help you build fact fluency?
Our students are better able to…
- Use strategies to add and subtract more fluently. (SMP 5, 7)
- Compute mentally by using the strategies efficiently. (SMP 7, 8)
- Provide ample opportunities for students to explore the strategies to build fluency. (SMP 5, 7)
- Emphasize the importance of using the strategies to become proficient math students. (SMP 7, 8)
- We use precise vocabulary fact families, inverse operations, and place value. (SMP 6)
2nd / Global Concept 2 of 2 for this Unit of Study: ApplyingAddition and Subtraction Strategies
The focus of this GCG is to use the addition and subtraction strategies in real world problem solving situations. / Projected Time Allotment:
4 days
Sample Essential Questions:
Day 1: How does using a part-part-whole mat help solve word problems?
Day 2:How does place value knowledge help you solve problems efficiently?
Day 3/4:How do you choose the best addition and subtraction strategy to solve a math problem?
Instructional Resources
Manipulatives:
- Part-Part-Whole Matto represent addition and subtraction scenarios.
- Base Ten Blocksto model addition and subtraction sentences.
- Dry erase boards/markerfor students to show their work.
- Open number lines as a tool for addition and subtraction.
- KWPR chart to help students answer problem solving questions.
- Common Core Addition and Subtraction Situations-gives examples of different ways to pose problem solving scenarios to students.
- Part-Part-Whole questions-Questions to provide for students to use the part-part-whole mat.
- Word Problems-Could be used on day 2 to practice using place value to add and subtract.
- Mixed Review Word Problems-These are word problems that can be used for days 3 & 4.
Sample HOT Questions: Use these to facilitate student discussions. (SMP 1 , 3)
- Which strategy is most efficient and why?
- Which strategy is least efficient and why?
- Is it ever appropriate to use more than one strategy when solving problems?
- How do you know which strategy to use?
Our students are betterable to…
- Use strategies to efficiently solve addition and subtraction word problems. (SMP 1, 2)
- Quickly solve problems because they are building fact automaticity through efficient strategy use. (SMP 5 , 7)
- Engage in conversations to justify their reasoning and evaluate others’ reasoning. (SMP 2,3)
- Give the students a number of opportunities to use the strategies and build proficiency with them. (SMP 2)
- Emphasize the importance of using efficient strategies and not just the ones students are most comfortable with using. (SMP 5, 7)
- Facilitate conversations with the students to justify their own thinking as well as other’s thinking. (SMP 2)