Randolph West continues a series on SQL Server data type storage:
If an integer or decimal amount is a precise representation of a value, a floating point is the closest approximation of that value in binary. Programming languages and databases use floating point numbers to trade storage (and memory) costs against precision. A floating point value is imprecise, but even that is underselling the problem.
Randolph also breaks all of the rules and writes out the largest FLOAT value you can have.