Grade Seven Students' Undstanding About Negative Number

Negative number is one of the most part of system of numbers and it's also thedifficult point of the Middle School mathematics teaching. Due to the effect of regularpsychological tendency, a number of feel difficult to study negative number in the beginning.This study investigates the understanding situation of Middle School Students'in theterms of the following 3 dimensions: the definition of negative number, therelationship of negative number and life and the operation of rational numbers withpurpose of understanding the students'cognition of negative number's essentialfeatures and finding the root cause which results in negative number concept'scognition difficult as well as raising teaching improvement measures.This study made the following conclusion through the questionnaire andindividual interview:1.7th grade students'representation of negative number takes on kinds ofpatterns. The most one is the pattern of "to add the minus in front of positivenumber" and the second is the pattern of "magnitude of scalar". The geometry patternis the third one.2. The students did not understand 3 meanings of "plus" and "minus".â‘ It represents an operator.â‘¡It is a symbol to indication whether a number is positive number or negativenumber.â‘¢"Minus" also represents opposite number.3. Most students are weak in comprehending the relationship of negativenumber and life, particularly using the real life situation to express a concrete rationalnumber expression.4. As to minus mixed number, the students know the integer part is negativenumber, but they regard the fraction part as positive number. They have somedifficulties in distinguishing -a²ⁿ from (-a)²ⁿ.5. As far as the cognition of the negative number concept, there is significant difference between 7th and 8th, 7th and 9th grade students, but there is no obviousdifference between 8th and 9th grade students. Meanwhile, there is no significantdifference between boy students and girl students in general. However, there is thesignificant difference between 7th boy students and 7th girl students and the girlstudents are better than boys.