The Effect Of Problem Character On Numerical Estimation And Its Strategy Of Primary School Student

Problem character refers to the characteristics of question itself, including thebackground, form, structure, spatial location and so on. The external representationand the difficulty of relevant features is one of the two important aspects.On aprocess of convert a representation to another representation, as long as oneinvolving numbers to be estimated is numerical estimation, which include numerosityestimation, measurement estimation and computational estimation.Primary school students are in the important development stage of numericalestimation, but in our country, the research about numerical estimation just be paidattention gradually. The previous numerical estimation focuses on subjective factorssuch as age, gender, educational level, cognitive style. For study problem character isnot only beneficial to enrich the theory research, but also provides a researchfoundation for compile textbook and exercises book on learning estimation skills byunderstanding the role of task characteristics on different types of task.This research adopts the experimental method that require the third, fifth andsixth graders to solve self-made numerical estimation problem and to report problemsolving strategy choices, then analyse its strategy.The results showed as followed:(1) In the computational estimation task, relative to be confronted with numericalsymbol, the primary students solve problem in geometric representation have a betterperformance.(2) Whether the number line estimation or object graph estimation, the thirdgrade can better estimate the vertical than horizontal number line, and either a verticalor horizontal number line is presented, the third, fifth and sixth grades all possesslinear model representation.(3) Relative to other graphic arrangement, the rationality of estimation strategy ininhomogeneous and irregular graph estimation task is dramatically higher.(4) In computational estimation word problem, wording on whole-part activated complementation strategy, meanwhile, wording on succession activated matchstrategy.(5) Relative to the unfolded plane figure, in stereogram estimation task morestudents use effective strategies, which includes the dotted completion, the unititerative and reference point strategy, rather than invalid strategies such as roughguess, miscount the number.(6) In a task of estimate number of black dots, an arrangement with large blackdots and high density is more likely to produce strategy of overall estimation, the thirdgrade students were more likely to choose the strategy of combining together with thedecomposition with small black dots and low density.(7) Question forms and four arithmetic operative rules play a very important rolein arithmetic estimation of the sixth grade: performance in estimate fractions anddecimals is better than that of estimate integer, and performance in estimate addition(8) In number line estimation, with the length grow and the scale increase, thesecond, four and sixth grade students’ performance are weakened.(9) When estimate how many grids inside a square box, if narrow the discrepanybetween two types of grid, the absolute percent error would become larger.(10) In condition that the number of figure is high and range of adjustment islarge, rough mental arithmetic strategy is used. On the contrary, employ approximatefamiliar number, round-off number and filled with zeros are frequent strategy.(11) On the number line task estimation, in a longer number line, segmentationstrategy is used more frequently, while the scale of number line isn’t influenting theusage of segmentation strategy.(12) In the absence of interference stimuli, sixth grade students adopt overallperceived strategy, and as the interference stimulus became to accumulate,comparative strategy was greatly used.To sum up, the following conditions were drawn:(1) There were noticeably differences in performance, mental pattern andstrategy between different external representations.(2) Differences of performance and strategy also exist in different features relevant to difficult.