Numbers is an application to convert numbers from one numeral system into another. You can convert numbers with bases between 2 and 36 to numbers of any other base between 2 and 36. You can also convert numbers to a couple country-specific or historical numeral systems, like Roman, Japanese, Greek etc.
Numbers does also support floating point numbers when converting numbers from all the bases between 2 and 36. So in case you want to know how PI looks like in the binary numeral system, Numbers will show you the result.