Abstract
Sixteen Year 3 students were interviewed individually about two- and threedigit numeration concepts, before and after ten groupwork sessions. One group of questions asked students about values represented by each digit in a two-digit number. Responses revealed that some students had not developed the idea that the "tens" digit represents a collection of ones, but believed that it represented only its face value. Comparison of results before and after the groupwork sessions showed that a number of participants had improved understandings of values represented by individual digits at the conclusion of the study. These results have implications for how place-value concepts are developed with place-value blocks.