Sign, mantissa and exponent
The sign bit
When we want to store negative numbers in binary we can use a sign bit to identify if a number is positive or negative. The sign bit is the first bit in a binary number:
Example 1: The number 5 in signed binary
0 1 0 1 0
Example 2: The number -5 in signed binary
1 1 0 1 0
A 1 on the signed bit indicates a negative number, while a 0 indicates a positive number.
Mantisa and Exponent
0 . 1 0 1 1 0 1 0 0 0 1 1
In this example the green is the sign bit, the cyan is the mantissa and the pink is the exponent:
- Sign bit: Determines if the number is positive or negative.
- Mantissa: The number itself.
- Exponent: The power of 2.