An old calculator uses a seven-segment display, in which numerals are represented by different patterns of vertical and horizontal line segments. But the device is faulty and no longer shows any ...

For children who find math difficult or frustrating, or who just like to be challenged, there are many cool math games online to play for free. But are they useful? Research shows that the brain’s ...

Some of the most satisfying number puzzles require little mathematical know-how. In fact, cracking the one below calls for thinking that is quite nonmathematical. I don’t know where or when I first ...