The aim of this study was to explore what knowledge is required for solving arithmetic word problems. This study examined the determinants of problem solving skills by regression analyses. Eighty-three fifth graders took a set of word problem solving tests that evaluated problem comprehension and solution-planning skills. They also took a set of tests which evaluated their existing knowledge of calculation and operation, and some intelligence tests. Students' performance in the existing knowledge tests accounted for the variance in their problem comprehension skill. This result supported Sakamoto (1995) which showed that the knowledge of computational procedure mainly predicted the performances of word problem solving tasks involving fractions. On the other hand, their solution-planning skill correlated highly with the problem comprehension skill rather than their level of existing knowledge.

Key words: word problems, problem-solving process, existing knowledge, regression analyses