Each growth point represents substantial expansion in knowledge along paths to mathematical understanding (Clarke, 2001). The whole number tasks in the interview take between 15-25 minutes for each student and are administered by the classroom teacher. There are about 40 tasks in total, and given success with a task, the teacher continues with the next tasks in a domain (e.g., Place Value) for as long as the child is successful. Children’s responses are recorded on a detailed record sheet.