Ginsburg (1977) observed that children typically develop surprisingly powerful informal (everyday) knowledge of mathematics and that mathematical learning difficulties often arise when formal instruction does not build on this existing knowledge. By using meaningful analogies teachers can help connect new formal instruction to students' existing informal knowledge and thus comprehend and learn it. The chapters by Bofferding et al., Wessman and Enzinger, and Bishop et al. vividly underscore these key points in the domain of integer addition and subtraction. These chapters richly illustrate how children can make sense of this domain even before formal instruction. How--in the absence of meaningful instruction (e.g., meaningful analogies)--their informal knowledge has key limitations. How playing games that embody a meaningful analogy can be help children construct a deeper understanding of integer addition and subtraction. In brief, relating integer addition and subtraction to a meaningful analogy has important implications for both assessing and promoting this critically important knowledge. [For the complete volume, "Exploring the Integer Addition and Subtraction Landscape: Perspectives on Integer Thinking. Research in Mathematics Education," see ED612853.]