There are some basic properties of whole numbers any 3rd grader can tell you: Each number is represented by a single symbol, and followed by a single successor. Multiplication makes a number bigger; ...

The iPhone, up through iOS 6, comes with a standard calculator application. When you hold your phone in portrait mode, with the home button at the bottom, then the display for the calculator shows ...

For many elementary teachers, fractions have traditionally sprung to mind lessons involving pizzas, pies, and chocolate bars, among other varieties of “wholes” that can be shared. But in what many ...