0.31
Positional notation can be used with a base other than ten. Here is a number written using base two:
| 1 | 0 | 0 | . | 1 | 0 | 1 |
| 1×22 | 0×21 | 0×20 | . | 1×2-1 | 0×2-2 | 1×2-3 |
When a particular power of the base is not needed, the digit '0' is used for
that position.
If the base is two, the point
'.' is called a binary point.
In general, the mark used to separate the fraction from the whole number is called a radix point. In many European nations, the radix point "," is used.