Mayan and Chinese Systems

The Mayan System (Base-20)

Developed in Central America, this system used Base-20. It had a symbol for Zero (a shell shape), which was a major advancement.

Symbols

• Dot ($\bullet$): 1
• Bar (—): 5
• Shell: 0

Numbers were written vertically.

• Top Level: Multiples of 400 ($20^2$) [Wait, specific calendar counts varied, but pure math was base-20]
• Middle Level: Multiples of 20 ($20^1$)
• Bottom Level: Multiples of 1 ($20^0$)

The Chinese Rod Numerals (Base-10)

A decimal place-value system used for calculation on counting boards. It alternated between vertical (Zong) and horizontal (Heng) rods to distinguish positions (Units vs Tens vs Hundreds).

This prevented confusion when writing numbers like 11 (one vertical next to another vertical would look like 2).