Relative formula mass & moles

• find the relative formula mass of MgCl2 ?

  (magnesium is 24 and chlorine is 35.5)

  95
• what is the relative formula mass of KNO3 ?

  (potassium is 39, nitrogen is 14 and oxygen is 16)

  101
• number of moles equation ?

  mass in g / relative formula mass