Support Math Reasoning By Linking Arithmetic to Algebra Virginia Bastable GSDMC 2013

Developing Mathematical Ideas Professional Development for teachers Investigations in Number, Data, and Space 2008-for students Connecting Arithmetic to Algebra—book and on-line course With: Deborah Schifter of EDC and Susan Jo Russell of TERC Partially funded by the National Science Foundation

Early algebra Generalized arithmetic articulating, representing, and justifying general claims in the context of work on number and operations Patterns, functions, and change repeating patterns, number sequences representing and describing contexts of covariation using tables, graphs, symbolic notation

First Grade Ana = = = = 11

Grade 1 Video clip Teacher: Who knows 9 + 9? Class: Oh. My gosh. Amalia: 18, because if it were I would think it was 19… But it is Manuel: Its 18. If you add two more it would be 20. It would be two less off... It would be one less off and it would be 19 and then another 1 less off is 18.

Grade 1 Video Clip Teacher = = ? Coleman: 17. I know that is 18 and if you minus 1 from 18 you will be at 17. Student: You’re right Coleman: 9 is one more than 8. So this must be 1 less than

Identifying potential general claims

Key aspects of integrating early algebra into arithmetic instruction Investigating, describing, and justifying general claims about how an operation behaves A shift in focus from solving individual problems to looking for regularities and patterns across problems Representations of the operations are the basis for proof The operations themselves become objects of study

Construct viable arguments and critique the reasoning of others. They justify their conclusions, communicate them to others, and respond to the arguments of others. Mathematically proficient students are also able to compare the effectiveness of two plausible arguments, distinguish correct logic or reasoning from that which is flawed, and—if there is a flaw in an argument—explain what it is. Elementary students can construct arguments using concrete referents such as objects, drawings, diagrams, and actions. Such arguments can make sense and be correct, even though they are not generalized or made formal until later grades.

A generalization is… A claim you can make about the way numbers and operations work. A claim is general if it applies to a range of numbers, for instance, all whole numbers or all positive numbers.

What behavior of addition is being revealed in these examples? = = = = 56 Use the first problem to help you solve the second: = = = _____ = _____

Grade 1: Adding 1 to an addend 1.On Saturday, there were 5 girls and 5 boys in the pool. How many children were in the pool? 2. On Sunday, there were 5 girls and 6 boys in the pool. Can you use the answer from the other story to help you figure out how many children are in the pool on Sunday?

Grade 1: Adding 1 to an addend Saturday Sunday Girls Boys boy

Grade 3: Adding 1 to an addend

Megan: The picture could be used for ANY numbers, not just 3 and 4. I could have started with anything in one hand, and then anything else in the other hand, and put them together. If I got 1 more thing in either hand, the total would always only go up by 1.

Articulations using algebraic symbols If a + b = c then a + ( b + 1) = c + 1 a + ( b + 1) = (a + b) + 1

Initial student reactions =

The answer is to be placed here. You can’t have more than one number on the right. You can’t have that many plus signs The teacher made an error. I see how she tried to fix it, but you can’t do that.

Explanations for why = Take 1 off the 6 and put it on the 19. So it is = Do the computation. Since both are 25 they are equal. Use a story to show they are the same without needing to know the answer

Using a story situation as a tool for explaining why an equality holds---a third grade student If I had some candy and I shared with my friend, but then I decided to share more with her, we would still have the same amount even though I’m sharing more with her. If I had 20 pieces and my friend had 5 pieces the sum would be 25. But then if I gave her another one of my pieces so she has 6 we would still have 25 together. So it doesn’t matter how we share the candy the total will always be the same. Unless we go get more or we eat some of it.

Symbolic Interpretations for = a + b = ( a +1) + ( b – 1) a + (1 + b) = (a + 1) + b

Early algebra Notice a regularity about an operation Articulate the generalization Prove why the claim is true Compare behavior of the operations

=

7 – 4 and 4 - 7

What about subtraction? Will the same general claim be true or will it need to be modified? Try some examples—make representations— articulate the claim. Does it matter if you add to the subtrahend or the minuend?

Ways of Knowing Accepting on authority Trying examples Applying mathematical reasoning based on a visual representation or story context Proving using algebraic notation and the laws of arithmetic

What does it take to develop this practice? Mathematics questions or tasks that are challenging enough so it is useful to take in more ideas than just one’s own. Specific pedagogical moves on the part of the teacher to help students learn how to listen/critique the thinking of others. Regular and consistent opportunities to develop and build this habit

Teacher Practices Use of routines to provide a forum for students to notice, state, and test general claims. Development of representations such as actions with cubes, number lines, arrays, and story contexts as tools for reasoning about operations.

Teacher Practices Revisiting general claims and the arguments developed for them when the number system expands or as a different operation is explored. Exploring the connection between the general claim and computational strategies

Teacher Moves to support listening Teachers enact listening in their work with students Teachers use techniques during discussions to help students learn to listen and to continue listening behaviors.

Turn and talk Practice explaining in small groups Paraphrasing Index card to write responses first Representations can make an idea tangible and visible Looking across representations

Sentence Starters I have a connection with what ________ just said….. I think you are saying_________ (repeat in your own words) I agree with ________ because… I’d like to add to what ________ just said….

Conclusion Expand student thinking beyond finding a pattern to seeing how the patterns works Help your students to focus on the meaning of the operations Use representations to make ideas visible Support math discussion among students Look for connections between computational strategies and larger principles of mathematics

Next steps How can you modify math work you already do with students to incorporate the kind of thinking we have been describing in this presentation?

Speaker Evaluation Strongly Disagree Text your message to this Phone Number: Strongly Agree Disagree Neutral Agree ___ ___ ___ ___________ ” Speaker was well- prepared and knowledgeable Speaker was engaging and an effective presenter Session matched title and description in program book Other comments, suggestions, or feedback Example: 545 Great session! ” “30995

For more information about the Mathematics Leadership Program Contact Virginia Bastable at Check out our website at leadership/org