quick math computations

[stri ker]

I frequently need to do some basic calculations.  I have used the  
following within Vim for Integer calculations:

:echo (4+7)*3-14
19
My question is this:
Is there a way to do calculations with doubles instead of integers  
without piping to an external program like bc and then inserting into  
a buffer?
For example

:r!echo '491.41 - 29.74' | bc

works when putting the result into the buffer.

TIA,
Kevin