if I want to find the uncertainty for a certain molar mass containing 4 atoms of Oxygen, do I multiply the error and the MM by 4: like this 4(15.9994 plus of minus .0003) = 63.9976 plus or minus .0012 (distribute the 4?)

Question

or follow the rules for mult. of uncertainty which would be turning them into a percent, (.0003/15.9994 x 100) squaring the result, taking the square root and then do the mutiplication by 4? 63.9976 plus or minus .0075 % uncertainty?