Unraveling the Mystery of the MoLi Stone: Place Value and Numeration In this unit, Unraveling the Mystery of the MoLi Stone , students explore our numeration system in depth. Often this number system that they use everyday has become so commonplace that they never pay attention to that underlying structure. Yet this structure is the essence of understanding place value. We call our system a place-value system since each position or place has a value...