As students progress from working with whole numbers to working with integers, they must wrestle with the big ideas of number values and order. Using objects to show positive quantities is easy, but no physical negative quantities exist. Therefore, when talking about integers, the author refers to number values instead of number quantities. The values and order of numbers are foundational concepts that students rely on for adding, subtracting, and reasoning about quantities. This article presents a glimpse into students' developing ideas about integers and activities that can foster their understanding. First graders restructure their ideas about foundational number concepts when they encounter negative integers.