Chapter 16

# Ten Alternative Numeral and Number Systems

In This Chapter

Looking at numeral systems of the Egyptians, Babylonians, Romans, and Mayans

Comparing the decimal number system with the binary and hexadecimal systems

Taking a leap into the world of prime-based numbers

The distinction between numbers and numerals is subtle but important. A number is an idea that expresses how much or how many. A numeral is a written symbol that expresses a number.

In this chapter, I show you ten ways to represent numbers that differ from the Hindu-Arabic (decimal) system. Some of these systems use entirely different symbols from those you're used to; others use the symbols that you know in different ways. A few of these systems have useful applications, and the others are just curiosities. (If you like, you can always use them for sending secret messages!) In any case, you may find it fun and interesting to see how many different ways people have found to represent the numbers that you're accustomed to.

## Tally Marks

Numbers are abstractions that stand for real things. The first known numbers came into being with the rise of trading and commerce — people needed to keep track of commodities such ...

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