Effects of instruction on strategy types chosen by German 3rd-graders for multi-digit addition and subtraction tasks: An experimental study

In an experimental study, we implemented two instructional approaches to teach 73 3rd-graders from 17 school classes adaptive strategy use. The explicit approach encompassed the explicit teaching and practicing of selected strategies, whereas the problem-solving approach emphasized the analysis of task characteristics and the individual generation of strategies. Results from post- and follow-up tests after the intensive one-week intervention did not yield significant differences between the two approaches in the efficency and in the accuracy of the applied strategies. In this contribution we report an additional analysis of the data examining the types of strategies the students chose. Although both groups used efficient strategies, it turned out that they differed significantly in the types of strategies they chose.