How to work out the conductance of a wire?

What is the conductance of 25m of this wire

So I have worked out this is the formula
G=sigma x a / length
conductance= conductivity x area / length
conductance= 5.8×10^7 S m^-1×0.1964 / 25×10^-3
Now is this right? or do I have to convert 5.8×10^7 S m^-1, or have I made any other mistakes?

also while I’m at it my calculator keeps giving me fractions whenever I do a formula like this 0.5×10^-3 =½000 why?
it seems to only happen with – powers