12.3*70.95 a little bit weird



Hello,

I'm a new maxima user and new to this list.  Maxima is an excellent free
computation software. I like it.
 
However, the following sort of errors made me a little bit upset when i
was doing numerical computation.
I can understand that errors will be introduced during the transformation
between representation of binary and decimal systems.

%i1)  12.3*70.95
%o1) 872.6850000000001

while

%i2) 123*7095
%o2) 872685

( I did this with maxima 5.25 on a fedora 16 x8664 laptop)

I don't know much about how does maxima do it internally. This kind of
errors is difficult to detect and track. I want to find out a more
safely way of doing this kind of calculation, which ensures that it
won't introduce such errors. 

Could anyone give some suggestions on how to do it correctly?

Dan C.