“Man, I didn’t do nothing,” students often said to me when I spoke with them about their behavior. “My point exactly,” I replied. “If you didn’t do nothing, you must have done something.” It was after ...

Here you will find a video about addition and subtraction. Watch this, and then test your knowledge with a short quiz before exploring the rest of the collection. This section contains videos from our ...

The common-core math standards require that students learn the standard algorithm for multi-digit adding and subtracting—you know, the process in which you line the numbers up vertically to add or ...