Uncertainties of Dimensionless Units

[Qube]

I have a physics project, but how do I express the uncertainty of a dimensionless quantity?

E.g. how do I express the uncertainty of the coefficient of friction?

Do I just write 0.403 ±0.02?

 

[BluFoot]

The way you write uncertainty is fine. But there's not much point in putting the "0.003" if it's ± 0.02... Might as well write: 0.40 ± 0.02