Students' flexibility in solving two-digit addition and subtraction problems: Instruction effects

This study examined the effects of conceptually based instruction on the de velopment of students' procedural flexibility. Students from 10 2nd-grade c lasses (206 students) in 9 primary schools in the Netherlands participated in 1 of 2 different instruction programs: the Realistic Program Design (RPD ) or the Gradual Program Design (GPD). The RPD teaches conceptual understan ding along with procedural skills. The GPD emphasizes the acquisition of st andard procedures. Students' use of and preference for procedures were asse ssed as well as their ability to solve problems in 2 different ways. The RP D led to a higher level of flexibility than did the GPD on all 3 measures, suggesting that the RPD was better in teaching the students conceptual know ledge. In both programs, conceptual understanding seemed to precede procedu ral skill. However, skill and understanding were closer related in the RPD than in the GPD group.