Numeral system facts for kids
Quick facts for kids Numeral systems by culture |
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|---|---|
| Hindu–Arabic numerals | |
| Western Arabic Eastern Arabic Khmer |
Indian family Brahmi Thai |
| East Asian numerals | |
| Chinese Suzhou Counting rods |
Japanese Korean |
| Alphabetic numerals | |
| Abjad Armenian Cyrillic Ge'ez |
Hebrew Greek (Ionian) Āryabhaṭa |
| Other systems | |
| Attic Babylonian Egyptian Etruscan |
Mayan Roman Urnfield |
| List of numeral system topics | |
| Positional systems by base | |
| Decimal (10) | |
| 2, 4, 8, 16, 32, 64 | |
| 1, 3, 9, 12, 20, 24, 30, 36, 60, more… | |
A numeral system is a special way to write down numbers. Think of it like a language for numbers! For example, Roman numerals (like I, V, X) and tally marks (like ||||) are different numeral systems.
In our everyday system, "11" means the number eleven. But in another system called binary, "11" actually means the number three! This shows how important the system is.
A numeral is the symbol or group of symbols we use to write a number. It's like how the word "cat" is a symbol for a real cat. So, "11", "eleven", and "XI" are all different numerals that stand for the same number.
For a long time, people used systems like Greek numerals and Roman numerals. But eventually, the Hindu–Arabic numeral system (the one we use today) became the most common.
Contents
Understanding Number Bases
Different numeral systems use different sets of symbols. The number of symbols a system uses is called its base.
The Decimal System (Base 10)
Our normal counting system is called the decimal system. It uses 10 symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.
When we write numbers like "10", it means one group of ten and zero ones. Or, you can think of it as (1 times 10 to the power of 1) plus (0 times 10 to the power of 0).
The Binary System (Base 2)
Computers use a system called binary. It only uses two symbols: 0 and 1.
In binary, "10" means one group of two and zero ones. This is the same as the number 2 in our decimal system. So, 10 (binary) = 2 (decimal).
Other Number Bases
For bases larger than 10, we often use capital letters as extra symbols. For example, the hexadecimal numeral system (base 16) uses the numbers 0-9 and then the letters A, B, C, D, E, F.
- 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
- A (which means 10 in decimal)
- B (which means 11 in decimal)
- C (which means 12 in decimal)
- D (which means 13 in decimal)
- E (which means 14 in decimal)
- F (which means 15 in decimal)
Where Different Bases Are Used
Today, most people use the decimal system (base 10) for everyday math.
However, computers mostly use binary (base 2) for all their calculations. People who work with computers often use octal (base 8) and hexadecimal numeral systems (base 16) because they are easier ways to represent binary numbers.
Long ago, ancient civilizations used different bases:
- The ancient Sumerians used sexagesimal (base 60).
- People in Mesoamerica used base 20.
