Maya numbers were quinary-vigesimal, and the associated notation systems were positional. One system consisted of bars and dots. Positionality was maintained by a sign resembling a seashell. A second notational system consisted of glyphs that depicted leftward-facing heads. The earliest information about Maya numbers comes from Diego de Landa, the Conquistador who infamously burned all the Maya books he could find. De Landa described the Maya number system as reaching infinity, though the highest term meant twenty to the seventh power, or 12.8 billion. Maya calculating involved counters placed on a flat surface. In the 1970s, the Nepohualtzintzin, a vigesimal abacus with 13 columns of seven beads, was created from purported oral histories and artifactual depictions. This device represents a significant revitalization of the Mesoamerican vigesimal number systems and their complex mathematical traditions. Today, the seashell sign used as a placeholder is often called zero, but conceptually, it was unlikely to have had the same meaning that zero does in today’s Western system. Given its calendrical use, the Maya sign might have meant “completion,” rather than “nothing.”