Welcome back to our book study of Number Talks by Sherry Parrish. The study is sponsored by Tara, the Elementary Math Maniac. She is right on schedule, so if you want to read a discussion of chapters 7 & 8, feel free to visit her blog!
I have changed our schedule just a bit:
- Today I will be discuss chapter 6 of Number Talks.
- This Thursday I will discuss chapters 7 & 8 of Number Talks.
- Sunday we come to you with our Makin’ It Math mid-month linky.
- Then, I will wrap up our Number Talks book study the following Wednesday with a discussion of chapter 9.
We hope you will stop back and join us on the above dates!
To read past book study posts, visit our Number Talks Book Study Archive!
Chapter 6: How Do I Design Purposeful Addition and Subtraction Number Talks in the 3-5 Classroom?
The number talks presented in this chapter are organized by operations and strategies. A rationale for helping students develop each strategy is presented and specific instructions are given for their implementation.
Even if you are not using number talks, this chapter does an exceptional job of illustrating essential strategies for addition and subtraction.
First, Parrish stresses the importance of using number talks that focus on fluency with small numbers BEFORE moving on to using those that focus on computation with greater numbers. Number talks with small numbers help students focus on strategies rather than the magnitude of numbers and foster confidence. In this chapter, specific number talks are presented to bring about the use of specific strategies, but it is also understood that students will share other methods. “The ultimate goal of number talks is for students to compute accurately, efficiently, and flexibly.”
Addition Number Talks
Making Tens: Making ten is an essential strategy and should be a default strategy used by fourth and fifth graders. If this is not the case, Parrish suggest the use of the second/third grade making ten strategies presented in this chapter first. Once you see students using the making ten strategy in default, it is safe to move on. Being able to make tens is foundational for further understanding.
8 + 5
(8 + 2) + 3
10 + 3
Making Landmark or “Friendly” Numbers: This strategy requires the understanding that compensation can be used—taking from one addend and adding to another without changing the sum. When students make a landmark/friendly number, they understand that by doing so the numbers become easier to “work with”, as we say in our classroom. Parrish suggests giving students plenty of time to explore and experiment with the use of this strategy and why it works. Start by having students prove their thinking with tools.
25 + 26
(25 + 5) + 21
30 + 21
Doubles/Near Doubles: Selecting numbers that are close is important here.
39 + 39
40 + 40 = 80
80 – 2 = 78
Breaking Each Number Into Its Place Value: Use numbers that do not have an obvious relationship to one another. This will encourage the breaking apart of numbers into their values and adding them mentally from left to right.
18 + 31
(10 + 30) + (8 + 1)
40 + 9
Adding Up in Chunks: Parrish suggest that students should be using this strategy midway through the second grade year. “Adding up numbers in chunks builds upon adding multiples of ten by encouraging students to keep one number whole while adding chunks of the second number.”
45 + 38
45 + 30 = 75
75 + 8
(75 + 5) + 3
80 + 3
In helping my second graders develop all of the above strategies with “small” numbers, I have found it important to continuously explore and discuss the efficiency of each strategy.
Subtraction Number Talks
Removal or Counting Back: A sequence of problem for use with this strategy are not presented. Parrish discusses how this is naturally a strategy students will use. Most important–the discussion of when the strategy is efficient and inefficient.
Adding Up: When choosing equations to encourage the use of this strategy–choose minuends and subtrahends that are far apart and frame them in a context that implies distance.
60 – 18
Our class has collected 18 cans for the food drive. Our goal is to collect 60 cans. How many more cans do we need to collect to meet our goal?
I have found it especially helpful to model mental thinking when adding up using an open number line.
Removal: Creating a context of removing an amount from a whole is important here. Parrish suggests encouraging students to keep the minuend intact and remove the subtrahend in parts.
60 – 18
You saved up 60 Muppet Bucks earned for exceptional effort and behavior. You cashed in 18 bucks. How many bucks do you still have saved?
Place Value and Negative Numbers: What’s important? You CAN “take a bigger number from a smaller number”. Starting with problems that have a difference of -1 is suggested. The following example shows a sequence of problems that can be used to illustrate this strategy.
Start with 4 – 4, move to 4 – 5, 4 – 6, and then 4 – 7
Adjusting One Number to Create an Easier Problem: This strategy involves the adjustment of the minuend or subtrahend to make a “friendlier” number. It is important to keep in mind when this is done that an adjustment to the answer must be made.
60 – 29
60 – 30 = 30
30 + 1 = 31
Keeping a Constant Difference: The difference/space between the minuend and subtrahend remain constant when the minuend and subtrahend are adjusted by the same amount.
25 – 8
27 – 10 = 17
I hope you find the overview of each strategy helpful, if you have not snatched up a copy of the book yet. It’s a phenomenal resource!
Please feel free to share your comments and/or take-ways from chapter 6!
AND– Just a reminder that this is our last day for collecting question for Sherry Parrish’s Q & A!
Here are the questions we have so far:
What suggestions do you have for the implementation of number talks as a building? Steps for beginning? Unforeseen obstacles?
Do you ever use number talks with missing addends?
I teach fifth grade, and I have not used number talks. None of my colleagues before me have used number talks. Where do I begin?
Please share any question you have! Simply send them to firstname.lastname@example.org.
Looking forward to a discussion of Chapters 7 & 8 this coming Thursday!
All the best for a wonderful week–