Adapting to the outside fact Many, children internalize social number-names, but how do they externalize them when communicating about outside numerosity? Mastering Many, children use bundle-numbers with units; and flexibly use fractions and decimals and negative numbers to account for the unbundled singles. This suggests designing a curriculum that by replacing abstractbased with concrete-based psychology mediates understanding through de-modeling core mathematics, thus allowing children to expand the number-language they bring to school. | De-modeling numbers, operations and equations: From inside-inside to outside-inside understanding