1. The problem statement, all variables and given/known data Calculate "f" and its uncertainty, watch the units, show all work. 2. Relevant equations f(x,z)= z/x x=100.5(+ or -) 3.8 cm y=71(+ or -) 1 s 3. The attempt at a solution ok so i know that to find uncertainty i have to use the equation delta f(x,y)=df(x,y)/dx *(delta x) + df(x,y)/dy * delta y. I got (delta f)= z*lnx*(delta x) + (delta z)/x. When i plug in the numbers the units dont match up, i get cm*s + s/cm. im really confused on how to find the answer can someone please help. thanks.