need a hand with union print
 

Hy everyone
I need a help for the union print in word (i don't know if is really "union print" in english, i'm italian and we say "stampa unione").
My problem: when i try to insert a date (by an excel file, a number), word should write it just like as it is, right? in my case, the number is everytime a little bit less than the real.
i have to write 3,17, but it write 3.169999999999999998...
someone knows the solutions at this problem? please, i need it for my job, and it's very important to me..
(apologies for my incorrect english, hope it's understandable)

thanks a lot