The Effect Of Working Memory Capacity And Problem Complexity On Junior Middle School Students' Integer Computational Estimation

Basing on the review and evaluation of the computational estimation research, this dissertation identified four objectives as follows:1.To probe into the effect of working memory capacity on computational estimation ability of the junior middle school students'integer addition;2.To probe into the effect of working memory capacity on computational estimation ability of the junior middle school students'integer multiplication.Using the literature method, interview method, experimental method and other methods comprehensively, this dissertation selected two groups of 22 junior middle school students with high or low working memory capacity as the research test subject. The tool of this dissertation is the self-made computational estimation material of integer addition and integer multiplication.Six findings were obtained:1.Working memory capacity has a conspicuous effect on the relatively complex problem of integer addition computational estimation which solved by junior middle school students. The questions of five and seven digit capacity computational estimation accuracy of the junior middle school students who have high working memory capacity are more significant than those junior middle school students who have low working memory capacity. The question of five digit capacity computational estimation time of the junior middle school students who have high working memory capacity are more significant than those junior middle school students who have low working memory capacity. But the opposite result was obtained in the question of five digit capacity.2.Working memory capacity has a conspicuous effect on the question of integer multiplication computational estimation of appropriate up-regulated strategy, one multiplier appropriate up-regulated strategy and one multiplier appropriate down-regulated strategy solved by junior middle school students. Compared with the junior middle school students who have low working memory capacity, he integer multiplication computational estimation ability of accuracy of the junior middle school students who have high working memory capacity is more conspicuously high and its reaction time is much shorter.3.Problem-size effect has existed in the question of integer addition computational estimation and integer multiplication evaluation solved by junior middle school students. Compared with the question of larger operand, the computational estimation accuracy of the smaller operand question which solved by the junior middle school students is conspicuously higher and its reaction time is conspicuously shorter.4.The type of carry propagation's influence of junior middle school students who have low working memory capacity is much higher than that of the junior middle school students who have high working memory capacity. Except the level of no carry and carry one bit, the difference of other levels of the computational estimation time of the junior middle school students who have low working memory capacity is significant.5.The characteristics of subject appropriate strategy's influence on the accuracy and reaction time of the integer multiplication computational estimation of junior middle school students who have low working memory capacity is much higher than that of the junior middle school students who have high working memory capacity. The differences of computational estimation's deviation degree of the junior middle school students who have low working memory capacity of the three different kinds of strategy characteristics subject are significant. From small to large extent, the deviation degree is as follow: appropriate down-regulated strategy, one multiplier appropriate up-regulated strategy subject and one multiplier appropriate down-regulated strategy subject and appropriate up-regulated strategy. Theirs estimation time from fast to slow is as follow: appropriate down-regulated strategy, appropriate up-regulated strategy and one multiplier appropriate up-regulated strategy subject and one multiplier appropriate down-regulated strategy subject.6.The characteristics of integer addition computational strategy of junior middle school students are diversity. Adjusting and decorating the result is the most effective computational strategy. Usage frequency of junior middle school students who have high working memory capacity is obvious higher than the junior middle school students who has low working memory capacity. Junior middle school students'strategy of integer multiplication computational estimation is so simply. Both junior middle school students of high working memory capacity and those who have lower working memory capacity tend to use rounding strategy. But only junior middle school students of high working memory capacity can select three of the rounding strategy flexibly and junior middle school students of low working memory capacity tend to use the down-regulated strategy.