Teaching the Concept/Meaning of Sum
Date: 10/23/2001 at 19:32:14 From: Linda Atamian Subject: Teaching the concept/meaning of sum I am a teacher working on math curriculum documentation. Today the word "sum" came up. The discussion was about teaching the meaning of the word sum to students in grades 1-5. I was surprised by the definition used by my colleagues. And I was further surprised by the definition in the few math glossaries I found online. To me "the answer to an addition problem or equation" is not a true or necessarily useful definition. I define the sum as the whole or total. With that definition I can say, if the sum is 10 finish the equation: 10 = 4 + __. 0r when we are writing a related subtraction fact I can say, begin with the sum: 2 + 3 = 5 so ___ -3 = 2 or ___ -2 = 3. I also find that if the equation begins with the sum and the students must find a missing addend, they need to know the sum is what they are beginning with, not the result of solving the equation: 5 = 2+ ___? Am I way off target here? As a math teacher I stress understanding, not correctly answering questions or problems, although my experience is that children are correct when they understand what they are doing.
Date: 10/23/2001 at 23:01:51 From: Doctor Peterson Subject: Re: Teaching the concept/meaning of sum Hi, Linda. I fully agree that understanding is important, and that we should be clear in our use of words. But I think the issue in the cases you are talking about is not really the definition of the word "sum." It's the misuse of the word "problem," which I often see in questions we receive. Here's a proper definition, from Merriam-Webster (m-w.com): 5 a (1) : the result of adding numbers (sum of 5 and 7 is 12) The sum is the RESULT of an addition, not the ANSWER to an addition PROBLEM. This is what the authors of the definitions you found mean, but their wording can be confusing in just the way you describe. A "problem" is a challenge given to a student, and as you say, _ + 2 = 5 is a problem involving addition in which the answer is not the sum but an addend. An "addition" (or, if you prefer, an addition "equation") is a statement of the form 2 + 3 = 5, in which two numbers are added, producing the sum as the result. Students too often fail to use clear words like "equation," calling it a "problem." This makes it hard to distinguish between the object they are working with and what they are to do with it. If we use these words carefully, then there is nothing wrong with saying the sum is a result - not the answer to the particular task (problem) they are working on, but the outcome of an addition operation that is implied in the problem. On the other hand, it would be just as dangerous to define the sum in this context as "the whole," because there are many problems involving a whole that don't involve addition, (say, fraction problems), and many addition problems in which the sum is only part of something. That's why I don't agree with your solution to the "problem." You're just a little bit off-target. What do you think? - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/
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