“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 ...

The National Council of Teachers of Mathematics is a public voice of mathematics education, providing vision, leadership, and professional development to support teachers in ensuring mathematics ...

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 ...

Same signs give a positive: \(3 + (+2) = 3 + 2 = 5\) Same signs give a positive: \(3 - (-2) = 3 + 2 = 5\) Different signs give a negative: \(3 + (-2) = 3 - 2 = 1 ...

We consider the problem of classifying all positive-definite integer-valued quadratic forms that represent all positive odd integers. Kaplansky considered this problem for ternary forms, giving a list ...