| Multiplication of rational number is always difficult in teaching,especially two negatives make a positive,which is taught by most teachers directly throughmultiplication rule.Therefore,students do exercise just by rote memorization of the rule instead of real understanding of how this rule works,let alone they can really know why negativemultiply positive is negative and two negatives become a positive.The thesis adopts documentary method,survey method and other research methods to do comparative study on the teaching contents for multiplication of rational number in four versions of textbook,Hunan Edition,PEP Edition,Beijing Normal University Edition and Zhejiang Edition.Through studying,there are some research results.First,textbooks of PEP Edition and Beijing Normal University Edition both summarize the rule of rational number multiplication by the way of plausible reasoning,among which textbook of PEP Edition makes a conclusion by seeking for regular pattern in order to strengthen students basic knowledge and skill,and textbook of Beijing Normal University Edition firstly links mathematical issue with real life,and then makes a summarize.In addition,textbook of Hunan Edition is more straightforward,which uses number axis as introduction,practical example in middle school student’s life as case,problem as guidance to deduce multiplication rule of rational number on the basis of distributive law of multiplication.Last but not least,textbook of Zhejiang Edition deduces this rule by adopting change of signs for opposite number,during which also uses analogy method.However,there is no real life connecting among the whole deduce process.To sum up,each edition of textbook has its own characteristic.The final goal of this thesis is to find a proper way of teaching to let student accept and propose a relatively representative teaching case to provide many front-line teachers with referential suggestion. |
