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Mrs. Reeder, Math, 2nd Grade

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Math Update 12/4/23 - 12/8/23

Last week, students learned the strategies, “Use Addition to Subtract on an Open Number Line,” and “Decompose to Subtract.”  

With the strategy, “Using Addition to subtract,” students will use their knowledge of how to count on from the smaller number.  

With the strategy, “Decompose to Subtract,” students will break apart the number being subtracted to get to a decade number. Then, students will subtract the other partner number to find the difference.  

For example: 

 53 - 7 =?  

Break the 7 into a 3+4 

Subtract: 53 - 3 = 50, then 50 - 4 = 46.  

So, 53 – 7 = 46 

At the end of the week, we started to learn about the strategy of compensation. That is where we will pick up again this week. Compensation to subtract was confusing to students, so we will be spending more time on that. You can watch this video if you are interested in learning how this strategy works. 

Next, we will focus on solving 2-step word problems involving subtraction. I hope to end the week with the Chapter 5 Post-test. 

Math Update 11/27/23 - 12/1/23

Math 

Before Thanksgiving break, students took the Chapter 4 Post-test and Chapter 5 Pre-test. At the end of the week, students learned to use the strategy of using an open number line to subtract two-digit numbers. The YouTube video in the previous link is a great explanation of the strategy if you are interested.  

This week, we will learn the strategies, “Use Addition to Subtract on an Open Number Line,” and “Decompose to Subtract.” 

With the strategy, “Using Addition to subtract,” students will use their knowledge of how to count on from the smaller number.

With the strategy, “Decompose to Subtract,” students will break apart the number being subtracted to get to a decade number. Then, students will subtract the other partner number to find the difference.  

For example: 

 53 - 7 =?  

Break the 7 into a 3+4 

Subtract: 53 - 3 = 50, then 50 - 4 = 46.  

So, 53 – 7 = 46 

Donation Request

Donation request:  

I am trying to put together a hands-on timeline of the telephone. I have a rotary phone from the 1950’s, a corded push-button phone from the 1980’s, and the school’s classroom phone.  

If you have one of these phones and are looking to part with them, our class would love to give them a new home! 

Math Update: 11/13/23 - 11/17/23

Last week, students learned how to add 3 two-digit numbers. We focused again on adding 2-step word problems. Students continue to struggle to determine which numbers to add for the first step and which numbers to add for the second step. This will be an ongoing concept for 2nd grade.

This week, we will take our Chapter 4 Post-test and Chapter 5 Pre-test. Then we will begin learning strategies to subtract 2-digit numbers. 

Math Update: 11/6/23 - 11/9/23

Last week, students learned the traditional algorithm that many of us grew up knowing as, “carrying.” It is now called “Regrouping.” 

This week, we will learn how to add 3 two-digit numbers. In addition, we will once again be focusing on two-step word problems, which is a struggle for many students. The problems are broken down into two individual steps. Students continue to apply strategies they’ve learned to add two addends at each step.  

Example: 

“You have 18 acorns and find 19 more. Your friend has 32 acorns. How many acorns do you and your friend have in all?” 

Step 1: Me: 18 + 19 = 37 

Step 2: Me and my friend: 37 + 32 = 69 

Math Update: 10/23/23 - 10/27/23

Math 

Last week, students used the strategies, “Decompose to Add Tens and Ones,” and “Compensation.”  

When students use “Decompose to add Tens and Ones” they will break apart only one addend into tens and ones. Then they will add the tens to the first addend, then add the ones.  

   24 ----> 20 + 4 

+ 35

     20  

    +35 

      55          55+4 = 59 

 

When students use “Compensation” they will take ones from an addend to make the other addend a ten. 

37 + 16 = ? 

+3     -3 

40 +  13 = 53 

 

Remember, the goal of this unit is to give students a variety of strategies that they are comfortable with.  This will allow them to choose an efficient strategy depending on the situation or the numbers being added.  

This week, we will be focusing on two-step word problems, which is a struggle for many students. The problems are broken down into two individual steps. Students continue to apply strategies they’ve learned to add two addends at each step.

Example: 

You have 18 acorns and find 19 more. Your friend has 32 acorns. How many acorns do you and your friend have in all? 

Step 1:

Me: 18 + 19 = 37 

Step 2:

Me and my friend: 37 + 32 = 69 

Math Update: 10/16/23 - 10/20/23

The week before break, we began Chapter 3, “Addition to 100 Strategies.” Students learned how to use the strategy “Use Place Value to Add.” This strategy is a precursor to the strategy that we all learned in school, “Carrying.” The traditional algorithm of “Carrying” and “Borrowing” is now referred to as “Regrouping.” When using place value to add, we break both numbers into their expanded form and then add them together.  

  24 ---->  20 + 4 

 +35 ----> 30 +  5  

  50 + 9 = 59 

 

This coming week, students will use the strategies, “Decompose to Add Tens and Ones,” and “Compensation.”  

When students use “Decompose to add Tens and Ones” they will break apart only one addend into tens and ones. Then they will add the tens to the first addend, then add the ones.  

   24 ----> 20 + 4 

+ 35

     20  

    +35 

      55          55+4 = 59 

 

When students use “Compensation” they will take ones from an addend to make the other addend a ten. 

37 + 16 = ? 

+3     -3 

40 +  13 = 53 

 

Remember, the goal of this unit is to give students a variety of strategies that they are comfortable with. This will allow them to choose an efficient strategy depending on the situation or the numbers being added.  

Math Update

This past week in math, we continued our unit on addition and subtraction strategies within 20. Lessons this week included strategies such as adding in any order and using doubles and doubles +1. We also learned how to add 3 single-digit numbers. This coming week we will be working with subtraction of single-digit numbers.

Math Update Mon. 8/28/23 - Thur. 8/31/23

This past week in math, we learned about even and odd numbers, as well as equal groups of objects and how they relate to repeated addition. (3+3+3=9). We held our first Math Workshop lesson, where students worked with partners and groups to solve one complex problem that had multiple correct solutions.

            This coming week in math, we will begin our unit on addition and subtraction strategies within 20. This means that students are working on learning strategies to solve single-digit addition and subtraction problems, learning how subtraction is related to addition so they can use addition equations to help solve subtraction problems, as well as working on knowing these facts automatically.

            Our first lesson in this unit will focus on adding in any order to find a sum. For example, 8+9 has the same sum as 9+8. In the following lessons, we will also learn the strategies of using doubles and doubles +1 (8+8=16, so 8+9=17). We will finish up the week learning how to add 3 single-digit numbers by strategically picking the numbers to add (for example, 6+4+4 could be solved by adding 6+4 first and then the other 4, or by adding 4+4, and then the 8).