Numerical digit facts for kids

These three numbers are not three digits; they are numbers made of digits. (e.g. "21" has two digits just as "480" has three digits.)

Numerical digits are the single symbols or characters we use to write down numbers. Think of them as the building blocks for all numbers. For example, the number "56" is made up of two digits: the digit 5 and the digit 6.

In the decimal system, which is the most common number system we use every day, we have ten different digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. This system is also called "base 10" because it uses ten unique symbols.

Each digit in a number has a special value based on its position. This is called "place value." For instance, in the number "56":

• The digit 6 is in the "ones" place (or 10 to the power of 0). So, it means 6 x 1.
• The digit 5 is in the "tens" place (or 10 to the power of 1). So, it means 5 x 10.

When you add these together (6 + 50), you get the number 56.

Some numeral systems use more than ten digits. For example, the hexadecimal numeral system (which is base 16) uses 16 different digits. It uses the usual 0 through 9, but then it also uses letters A, B, C, D, E, and F to represent the values 10 through 15.

Understanding Different Number Systems

Digits are essential for writing numbers in any system. While the decimal system is common, other systems exist for different purposes.

The Decimal System (Base 10)

The decimal system is what you use for counting, money, and almost everything else. It's based on powers of 10. Each place a digit holds represents a power of 10.

• The first digit from the right is the ones place (10^0 = 1).
• The second digit is the tens place (10^1 = 10).
• The third digit is the hundreds place (10^2 = 100), and so on.

This makes it easy to write very large or very small numbers using just a few digits.

The Hexadecimal System (Base 16)

The hexadecimal system is often used in computer science. It's a base-16 system, meaning it needs 16 unique symbols. Since we only have 10 number digits (0-9), we use the first six letters of the alphabet to complete the set.

• 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
• A (represents 10)
• B (represents 11)
• C (represents 12)
• D (represents 13)
• E (represents 14)
• F (represents 15)

This system is useful because it can represent large numbers with fewer digits compared to the binary system (base 2) that computers use internally.

Related pages

• Digital

See also

In Spanish: Cifra (matemática) para niños