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Two-Digit Addition and Subtraction

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Two-Digit Addition and Subtraction

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

- 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 =

How do these tasks connect to the Grouping Tens videos?

- 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?

- 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

Roll and Add

- Log into amcanywhere.com
- Complete the assessment as we watch Brian

Brian

What did he score?

What evidence was there about his mathematical understanding?

What questions do you have about Brian’s understanding?

- 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

Add ‘Em Up - Lots of Lines

Partner Add-It

Add ‘Em up- Yarn Shapes

11:30-12:45

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.

- Read p. 106-107
“Subtracting Numbers to 100”

Read your assigned strategy.

Be prepared to share with the group:

1. What is the strategy?

2. Show an example

3. How does it relate to the assessment?

Roll and Subtract

Two Ten Shapes Subtraction

Partner Take Away

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.

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?

Assess your students….

- 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

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