BRAINERD, Minn. -- Consider this math problem: Find the square root of 49, double it, minus 5, square it, subtract 1, divide by 4, cut in half, cut in half, subtract 1, divide by 2, cut in half, cut ...

Ever dreamt of solving math problems in your head with the speed of a calculator? Mental math might seem challenging, but it's a skill attainable through the right tools and techniques. The abacus, an ...