Design Research on Addition and Subtraction Up to 100udUsing Mental Arithmetic Strategies on an Empty Number LineudAt the 2nd grade of SDN Percontohan Komplek IKIP, Jakarta

摘要

In this design research, a conjectured local instruction theory is developed to help children enhance their mental arithmetic to perform addition and subtraction problems up to 100. Moreover, the development ofchildren’s learning process in mental arithmetic both individually and in a social community is analyzed to provide information for the refinement of the theory. This paper highlights mental arithmetic strategies to solve addition and subtraction problems up to 100 on an empty number line. Mental arithmetic can be defined as a way to handle numbers in a handy and flexible way. Contradicts to algorithm, mental arithmetic is characterized with number sense and number relations. Findings from the first phase of this design research show that children at the second grade perform algorithm without sufficient understanding of numbers. Hence, realistic approach that encompasses mental arithmetic strategies on an empty number line is suggested as an alternative to help young children in solving addition and subtraction problems flexibly and meaningfully.