# Class Presentation Topics

EGYPTIAN
Egyptian mathematics
The Egyptians used hieroglyphic symbols for their numerals. They had no zero, so it is not a true base ten system.
BABYLONIAN
Why base 60?
Babylonian numbers
Babylonian mathematics
Base 60 is useful because so many numbers divide into 60.
DUODECIMAL
Base 12
Dozenal society
Base 12 is a favorite because it is easily divisible by many factors. The system still lingers today in our 12 hours, 12 months, 12 inches per foot, 12 eggs per dozen, etc.
INCAN
Quipu
The Incans used a line of knotted strings to keep records of inventories. The size, color, and length of each string/knot were important.

CHINESE CHARACTER SYSTEM Tiffany
Chinese
Chinese hand system

The Chinese use characters for their numerals. They also have two different number systems, one for the general usage and a formal one for banking.
STICK MATH or NUMERAL RODS
Counting rods
Asian cultures adopted this method before the abacus.
YORUBAN
Yoruban system
The Yoruban people of Nigeria use a combination of base 5/base 20. Their system is based on counting cowrie shells.

MAYAN
Base 20
Mayan

The Mayans were some of the first to use zero.
BINARY
Birthday cards

Base 2
Binary fingers
Computers only deal with the numerals zero and one, which correspond to ON or OFF.
ROMAN
Roman numerals
You should be glad we don't use this system today!
HEXIDECIMAL
Base 16
Base 16 for computers is also related to the binary system.

HAWAIIAN
Hawaiian number system
Base 4

Based on counting fours