Today's study breaks down the different skills needed by a student to be able to complete an algebra problem. It turns out that there are four separate types of knowledge needed, and a person must master the easiest before progressing to the next, etc. So, without further ado, here is:

"A Developmental Model for Algebra Symbolization: The Results of a Difficulty Factors Assessment", by Neil T. Heffernan and Kenneth R. Koedinger. Published in Proceedings of the Twentieth Annual Conference of the Cognitive Science Society, 1998, edited by Morton Ann Gernsbacher and Sharon J. Derry, pp 484-489.

The Experiment

During the first month of school, 74 urban ninth graders enrolled in a regular-level algebra class were given a test made by the experimenters that included word problems of different levels of complexity.

The first type asked for each student to make a single-operation formula out of numbers. Example: "Sue made 72 dollars by washing cars to buy holiday presents. She decided to spend 32 dollars on a present for her mom and then use the remainder to buy presents for her sisters. How much can she spend on her sisters?" Answer: 72-32.

The second type asked for each student to make a single-operation formula out of a combination of numbers and variables. Example: "Sue made 72 dollars by washing cars to buy holiday presents. She decided to spend 'm' dollars on a present for her mom and then use the remainder to buy presents for her sisters. How much can she spend on her sisters?" Answer: 72-m.

The third type of question asked each student to make a double-operation formula out of only numbers. Example: "Sue made 72 dollars by washing cars to buy holiday presents. She decided to spend 32 dollars on a present for her mom and then use the remainder to buy presents for each of her 4 sisters. She will spend the same amount on each sister. How much can she spend on each sister?" Answer: (72-32)/4.

The fourth type was the most challenging. Each student was asked to make a double-operation formula using both numbers and variables. Example: "Sue made 72 dollars by washing cars to buy holiday presents. She decided to spend 'm' dollars on a present for her mom and the remainder to buy presents for each of her 4 sisters. She will spend the same amount on each sister. How much can she spend on each sister?" Answer: (72-m)/4.

The actual questions were varied, such that any given test paper only had one question about Sue washing cars, but the test questions were all equivalent to the examples listed above and in the paper.

The Results

The lowest-performing students were able to do the simple arithmetic formulas (Type 1). The next step was to to the more complicated arithmetic expressions (Type 3). Once they are good at that, they start to understand the single-operator variable problems (Type 2). All students in the study who could correctly answer the Type 2 questions also correctly answered the arithmetic ones. The last step to being able to master algebra is the double-operator variable problems (Type 4).

Most people assume that it is the language used in word problems that makes algebra so hard; given the design of this experiment, the researchers have very conclusively shown that language comprehension is not the issue. After all, the language used in the Type 2 and 4 problems was exactly the same, and yet one was significantly more difficult than the other.

The researchers ran a separate experiment to see what is needed by students to make that final leap into fully grasping algebra. Since it seemed like students have trouble combining multiple steps together when there are variables involved, they trained some students for an hour on the following types of problems, dubbed symbolic substitution problems: "Let X=72-m. Let B=X/4. Write a new expression for B that composes these two steps." Answer: (72-m)/4. Student performance on algebra word problems increased after just one hour of practicing these sorts of problems.

What this shows is that it is not only the language of word problems that needs to be understood, but the language of abstract mathematical concepts needs to be understood, as well. Not only do students have to understand what the problem says, but how to create the right abstract representation, which are two very different things!

Here's a way of thinking about it: Lots of people say that if you can read, you can cook. My husband says that this baloney, because he can read, but he can't cook--cookbooks are written in a foreign language, as far as he in concerned! All of those verbs mean something very specific, and involve skills that he generally does not have; everything is also written in shorthand. He says it's like this: If you can read a cookbook and perform all of the required actions, then you can cook!

How Waldorf Education Teaches Algebra

Arithmetic is introduced in the first grade, and its form takes on both of the first two types of algebra skills, both inside and outside of oral word problems. For instance, they try to figure out what can be added to 7 to equal 12 (a type 2 problem). This early work with numbers and variables skips over the work with complex number problems; however, this is gradually introduced the next couple of years with number adventures, where the children do a lot of operations to a given starting number in their heads. While they may not be writing down these concepts, they are busy internalizing them.

The final step is introduced slowly over the 6th-8th grade years (particularly in 8th grade), as the children work with formulae that they have themselves discovered, the manipulative rules of algebra (many of which they discovered but did not name back in first grade, like 1+3=4 and 3+1=4 (the commutative property)), polynomials (which can be designed into symbolic substitution lessons), and finally, algebra word problems.

The early, deeply-ingrained numeracy lessons of the Waldorf curriculum lay an excellent foundation for introducing the abstract concepts of algebra; based on the study and my inquiries with a Waldorf teacher, the hurdles that the students need to jump over are slowly laid out in a logical way, making 8th grade algebra a fun, playful challenge, instead of drudgery.

## Sunday, July 1, 2007

### Learning Algebra, In Steps

Posted by Jeff at 2:37 PM 10 comments Links to this post

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