Forbes contributors publish independent expert analyses and insights. The tactics everyday people use to “FIRE” and pursue their dreams. If you want a tough challenge to address in your spare time, ...

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 ...

OK, Ari, what is 567 times 123? And you have exactly three seconds to answer, so you better move fast. SHAPIRO: You can't be serious right now, Juana. SUMMERS: (Laughter). SHAPIRO: There's no way ...