Radix point facts for kids
A radix point is a special symbol that helps us separate whole numbers from parts of numbers (called fractions). Think of it like a fence that divides the "whole" part of a number from its "piece" part. The most common radix point you use every day is the decimal point, which is used in our base 10 number system. For example, in the number 12.75, the decimal point separates the whole number 12 from the fractional part 75.
Different number systems use different names for their radix points. For instance, in the binary system (which computers use), it's called a "binary point." While many English-speaking countries use a small dot (.), other countries might use a comma (,) instead.
How Numbers Work with a Radix Point
When we write numbers, each digit has a special "place value." This value depends on how far the digit is from the radix point.
Let's look at the number 1234.56 in our everyday base 10 system:
| Place Value | Thousands | Hundreds | Tens | Ones | Tenths | Hundredths |
|---|---|---|---|---|---|---|
| Digit | 1 | 2 | 3 | 4 | 5 | 6 |
- The digits to the left of the radix point show the whole number part.
* The '4' is in the ones place (4 x 1). * The '3' is in the tens place (3 x 10). * The '2' is in the hundreds place (2 x 100). * The '1' is in the thousands place (1 x 1000). * So, the whole number part is 1000 + 200 + 30 + 4 = 1234.
- The digits to the right of the radix point show the fractional part.
* The '5' is in the tenths place (5 x 0.1, or 5/10). * The '6' is in the hundredths place (6 x 0.01, or 6/100). * So, the fractional part is 0.5 + 0.06 = 0.56.
When you put them together, you get 1234.56!
Different Kinds of Radix Points
The idea of a radix point is used in all number systems, not just base 10.
- Decimal Point: This is the most common one. It's used in the base 10 system, which has 10 different digits (0-9).
- Binary Point: Computers use the binary system, which only has two digits (0 and 1). A binary point separates the whole part from the fractional part in binary numbers. For example, 101.11 (binary) would be like 5.75 (decimal).
Want to Learn More?
- Floating point: Learn how computers handle very large or very small numbers.
- Fixed point: Discover another way computers deal with numbers that have fractional parts.
- Positional notation: Understand how the position of a digit gives it value.
- Scientific notation: See how scientists write extremely large or small numbers.
