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# Two-Digit Addition and Subtraction PowerPoint PPT Presentation

Two-Digit Addition and Subtraction. Time to assess kids will be inserted when we know what time that will occur!. Solve the following problem: 28 + 16 = ?. Without paper and pencil (please)

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#### Presentation Transcript

Time to assess kids will be inserted when we know what time that will occur!

### Solve the following problem:28 + 16 = ?

• Without paper and pencil (please)

• After you solve the problem, find a partner and show them how you solved the problem using the cubes as a model

• 38 +16 =

• 58 +16 =

• 28 +26 =

• 28 + 66=

• 48 +36 =

### Connect

How do these tasks connect to the Grouping Tens videos?

### Discussing the Video

• Video for 69+87

• What did you notice?

• What is the connection to the work that we have been doing?

• Read p. 102-105 in the red book

• What is the connection between place value understanding and addition work?

• What mathematical understandings do students need to have in place to be successful?

### Two-Digit Addition and Subtraction Assessment

• Can the student use the concept of tens and ones to add two-digit numbers, by mentally breaking them apart and reorganizing them into the total numbers of tens and ones, when the problem is present:

• Level 1: With a model

• Level 2: Without a model

• Level 3: Symbolically

Containers

Building Stacks

### Let’s try the Two-Digit Addition and Subtraction Assessment

• Complete the assessment as we watch Brian

### Let’s Assess Brian

Brian

What did he score?

What evidence was there about his mathematical understanding?

What questions do you have about Brian’s understanding?

### What comes nextfor Brian?

• Using the blue book, read p. 214-215

• Using the charts on p. 215-217

• Can you find which activities Brian needs at this point?

• Now find Roll and Add in your Developing Number Concept Books

### Station Time!

Add ‘Em Up - Lots of Lines

11:30-12:45

### Time for math

52-24=

Now we want you to come up with 6 related subtraction problems.

Two of them should include the number 52.

Two of them should include the number 24.

Two of them should include neither 52 or 24.

“Subtracting Numbers to 100”

Be prepared to share with the group:

1. What is the strategy?

2. Show an example

3. How does it relate to the assessment?

### Subtraction specific games…

Roll and Subtract

Two Ten Shapes Subtraction

Partner Take Away

### agree/disagree…

By the end of 2nd grade students need to have basic facts memorized (2 seconds or less).

By the end of 2nd grade students need to have multiple strategies and ways to think about subtracting 2-digit numbers.

By the end of 2nd grade students need to be proficient with the standard algorithm for subtraction.

By the end of 2nd grade, getting the answer to a 2-digit addition or subtraction problem efficiently (in a few quick steps) is a reasonable expectation.

### Connections to Investigations

What are the addition/subtraction strategies that students typically work with in 2nd grade?

How can this last assessment and the concepts in it support students’ strategies?

### Moving Forward

• Grant requires- Hiding Assessment 3 times

By Oct 15, By Jan 30, By May 30

• Other assessments based on students’ needs

Complete online modules

• Due dates- Oct 15, Jan 30, April 30

• On-line modules are all classroom-based and based on collecting data

Survey on experience...

Thank you for taking the time to complete this