Given 35.6 grams of Ca(NO3)2, how many formula units are present

Given 35.6 grams of Ca(NO3)2, how many formula units are present?
explain please

Convert to moles, then convert to molecules

(35.6g) / (164.09g/mol) = .217 moles

Now just multiply .217 by 6.022x10^23 (number of molecules in one mole) and you've got total formula units.

(.217)(6.022x10^23) = 1.31x10^23 formula units