USING ADDITION TO SOLVE SUBTRACTION PROBLEMS IN THE NUMBER DOMAIN UP TO 20 AND 100

Journal Article

Source:

MENON online Journal Of Educational Research, 1st Thematic Issue, University of Western Macedonia - Faculty of Education, Florina, Greece, p.19 (2014)

Keywords:

direct subtraction, flexible strategy use, mental arithmetic, subtraction by addition

Abstract:

Over the past 4 decades, a lot of research has been done on the strategies that are used to mentally solve subtraction problems. In the present manuscript, 2 types of strategies are distinguished: (1) direct subtraction, in which the smaller number is directly subtracted from the larger one (e.g., 75 − 43 = . by doing 75 − 40 = 35, 35 − 3 = 32), and (2) subtraction by addition, in which one determines how much needs to be added to the smaller number to get to the larger one (e.g., 75 − 43 = . by doing 43 + 30 = 73 and 73 + 2 = 75, so the answer is 30 + 2 = 32). We set up a series of 5 related studies using non-verbal methods to investigate the flexible use of these strategies in both single- and multi-digit subtraction, first in adults and then in both typically developing children and children with mathematical learning disabilities. The present article provides an overview of the results of these 5 studies.

Body:

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