How do you calculate molar mass? For example, what is the molar mass of #Cu(NH_4)_4SO_4#?
Well, this is simplicity itself; add the atomic mass of copper plus the atomic mass of sulfur...............plus 16 times the atomic mass of hydrogen.
All I have done is to sum the molar mass of each individual element, and weighted according to its occurrence in the formula. Are you happy with this?