The purpose of this project was to examine young children's mathematics learning using virtual manipulative touch-screen apps. We interviewed over 100 young children as they interacted with mathematics apps on iPads and examined how these interactions supported mathematics learning and contributed to changes in efficiency. Children interacted with six different mathematics apps under the direction of an interviewer. Results of the study indicated that children's learning and efficiency improved between the pre- and post-assessments during a short interview time period. Close alignment of the learning apps with the pre- and post-assessment apps contributed to these positive changes. To conduct this study, researchers created a variety of research tools that were not available because iPad research is still in its infancy. [For a related article, "Young Children's Learning Performance and Efficiency When Using Virtual Manipulative Mathematics iPad Apps," see EJ1048462.]