Teaching students to look for irrelevant or missing information in word problems appears to help them develop better problem-solving skills. A recent study carried out by Renae Low, Ray Over, Lawrence Doolan and Sue Mitchell, La Trobe University, Bundoora, Australia, examined whether teaching students to search the text of algebraic word problems for missing or irrelevant information increases the percentage of problems they correctly solve.
Experiment in text editing
Two hundred eight secondary students in Melbourne, Australia were tested twice on algebraic word problems. A pretest and post-test were administered eight to ten weeks apart. Both tests included some problems that contained irrelevant as well as relevant information. Prior to the post-test, some students were trained in detecting what information within the text of the word problems is necessary and sufficient for solution while others were given only routine practice in computation. Two other groups who were used as controls received no instruction.
Group One was given 80 minutes of instruction in text editing. The instruction focused on analyzing whether the text of the word problem contained sufficient or insufficient information for a solution, or information that was irrelevant. After the students had tried identifying the kind of information in
sample word problems, the teacher provided feedback by identifying the correct response and giving the reason for this choice. For example: “This is an area-of-rectangle problem. Since area equals length multiplied by width and only the length is given, the information provided in the problem is insufficient for solution.” The teacher did not solve any of the problems by working through the steps to solution.
Group Two received 80 minutes of instruction on the mechanics of problem solving. The word problems given to this group contained only information that was necessary and sufficient for solution. After the students had worked each problem, the teacher demonstrated the steps to the correct answer. The teacher did not direct attention to the text structure or the logic used to translate the word problem into a numerical equation.
Control Groups Three and Four received neither training in text editing nor practice in problem solving. Group Three, however (along with Groups One and Two), was cautioned to disregard any irrelevant information that might appear in the word problems on the post-test.
Students who received instruction in text editing showed significantly greater gains in post-test performance than other students. Those trained in text editing performed better on all types of problems, whether or not they contained irrelevant information. Students who scored lowest on the pretest appeared to benefit the most from this instruction by showing the greatest gains.
Low et al. conclude that training in text editing facilitates solution of algebraic word problems. Students derived greater benefit from training in text editing than from traditional instruction emphasizing computation skills. Searching the text for irrelevant or missing information apparently led students to ask what information was needed to solve the problem and how that information should be used. Also, simply alerting students to the possiblity that any problem they are presented with might contain irrelevant information improves their problem solving.
“Solution of Algebraic Word Problems Following Training in Identifying Necessary and Sufficient Information Within Problems”, American Journal of Psychology, Volume 104, Number 3. Fall 1994, pp. 423-439.
Published in ERN March/April 1995, Volume 8, Number 2