You add the mass of every element together. C= 12.011 since there is 4 of them you multiply that by 4, H= 1.007 multiply it by 8, O= 15.999 multiply it by 2, 48.044 + 8.056 + 31.998 = 88.098. The molar mass is 88.089 grams (all periodic table can contain different values)