• School Mathematics
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• v.11 no.3
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• pp.479-496
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• 2009

Some children can construct a basic concept of addition and subtraction during the preschool years. Children start to experience mathematics via numbers and their of operations and contact with various contexts of addition and subtraction. In special, word problems reflect mathematics which is appliable to real life. In this paper, I analyse the types of word problems in text book and its students' responses. First, I analyse the types of addition word problems which consist of change add-into situations and part-part-whole situations. Second, I analyse the types of subtraction word problems which consist of change take-away situations, compare situations and equalize situations. Third, I analyse the students' responses by the types of word problems in addition and subtraction. And 115 2nd grade elementary school students participated in this survey. The following results have been drawn from this study. First, the proposition of word problems of part-part-whole situations is higher than that of change add-into situations and the proposition of word problems of take-away situations is higher than that of compare situations and equalize situations. According to the analysis about students' responses, It is no difference between change add-into situations and part-part-whole situations. But the proposition of word problems of take-away situations is higher than that of compare situations and equalize situations. This results from word problems which contain unnecessary information in problem. So, we have to present the various word problems to students.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.7 no.1
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• pp.3-14
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• 1997

본 논문은 정보보호 기능의 실시간 처리를 위한 초고속 정보통신망에서의 정보보호에 관한 것으로 가입자-망이나 망-노드에서의 데이터 접속을 맡고 있는 ATM 물리계층내 구간처리기와 셀처리기에서의 정보보호 방안에 대하여 기술되었다.아울러, 국제 표준안에 제안되어있는 물리계층의 각 기능이 분석되어 있으며, ATM 물리계층내 구잔처리기와 셀처리기에서의 정보보호방안의 타당성에 관하여 기술되었다. 특히, DES암호 알고리즘을 이용한 구간 처리기에서 정보보호 기능과 IDEA 암호 알고리즘을 이용한 셀처리기에서의 정보보호 기능이 시뮬레이션을 통하여 확인되었다. 아울러, 본 논문에서는 정보보호기능이 내장된 ATM 물리계층용 집적회로의 구현 가능성 및 그에 따른 효율성에 대하여 기술되었다.

• Education of Primary School Mathematics
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• v.19 no.3
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• pp.177-191
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• 2016

Students can calculate the addition and subtraction problem using informal knowledge before receiving the formal instruction. Recently, the value that a computation lesson focus on the understanding and developing the various strategies is highlighted by curriculum developers as well as in reports. Ideally, a educational setting and classroom culture reflected students' learning and problem solving strategies. So, this paper analyzed the similarity and difference with respect to the numeric sentence and word problem in the addition and subtraction. The subjects for the study were 100 third-grade Korean students and 68 third-grade American students. Researcher developed the questionnaire in the addition and subtraction and used it for the survey. The following results have been drawn from this study. The computational ability of Korean students was higher than that of American students in both the numeric sentence and word problem. And it was revealed the differences of the strategies which were used problem solving process. Korean students tended to use algorithms and numbers' characters and relations, but American students tended to use the drawings and algorithms with drawings.

• Education of Primary School Mathematics
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• v.19 no.2
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• pp.127-142
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• 2016

The purpose of this study was to examine the students' problem solving ability according to numeric expression and the semantic types of addition and subtraction word problems. For this, a research was to analyze the addition and subtraction calculation ability, word problem solving ability of the selected $2^{nd}$ grade(118) and 3rd grade(109) students. We got the conclusion as follows: When the students took the survey to assess their ability to solve the numerical expression and the word problems, the correct answer rates of the result unknown problems was larger than those of the change unknown problems or the start unknown problems. the correct answer rates of the change add-into situation was larger than those of the part-part-whole situation in the result unknown addition word problems: they often presented in text books. And, in the cases of the result unknown subtraction word problems that often presented in text books, the correct answer rates of the change take-away situation was the largest. It seemed probably because the students frequently experienced similar situations in the textbooks. We know that the formal calculation ability of the students was a precondition for successful word problem solving, but that it was not a sufficient condition for that.