Give the name and calculate the molar mass for Fe NO3 3?

I presume you mean 'Fe(NO3)3'. Note the use of brackets to indicate the number of nitrate anions. Otherwise the 'stand alone' suffix '3' is meaningless. Or wrongly confused as '33' oxygen atoms'.

Note the use of Roman Numerals to indicate the oxidation state of iron.

Fe(NO3)3 is Iron(III)nitrate or Ferric Nitrate.

Molar Mass

Fe x 1 = 56 x 1 = 56

N x 3 = 14 x 3 = 42

O x 3 x 3 = 16 x 9 = 144

56 + 42 + 144 = 242 (The molar mass).

NB The 'N x 3' comes from the three nitrogen atoms, one each in the THREE nitrate anions.

Similarly The 'O x 3 x 3 comes from three oxygen atoms, in each nitrate anion. There being three nitrate anions, means that there 3 x 3 = 9 oxygen atoms in the molecule.

NNB Careful with the nomenclature. If there are only TWO nitrate anions present in the molecule , then the formula is 'Fe(NO3)2, and the name(s) are Iron(II)Nitrate or Ferrous Nitrate.

NNNB 'Fe' is the chemical symbol for Iron. It comes from the Latin for Iron, which is 'Ferrum (Fe)'.