Don't Cross The Streams (FP scientific calculator serial co-processor)

mrburnette:
But to answer the original question, I do not see why you could not offload to a math coprocessor.... surely would run up the co$t for a single-percision FP solution.

There's a double precision version of the chip. That would give whole new capabilities to the Arduino (double precision math isn't supported by the Arduino libc).

http://www.micromegacorp.com/umfpu64.html