In this chapter, we described a study that compared a problem-based learning (PBL) approach to a traditional approach for teaching decimal concepts to 76 Chinese fi fth graders. This chapter started with a review of literature regarding conceptual change, challenges in teaching decimals to elementary students, the PBL in relation to selfeffi cacy, and the rationales for conducting the present study. Then, we elaborated the PBL approach as an intervention approach in an independent sample of fi fth graders. Finally, we discussed implication of PBL in educational settings.Decimal fraction learning is considered one of the cornerstones of mathematics education internationally (Stacey et al., 2001 ). In the United States, formal instruction of decimal fractions begins in fourth grade and continues throughout all secondary grade levels (National Council of Teachers of Mathematics (NCTM), 2000 ). The NCTM Standards require third to fi fth graders to be able to understand and convert fractions, decimals and percentages. And students older than sixth graders should fl exibly solve problems involving fractions, decimals and percentages. In China, decimals and fractions are also introduced to students at the elementary level beginning in fourth grade (Zong, 2006 ).