Mr de NaCl > 1 x Ar Na = 23 ~ 1 x Ar Cl = 35 ~ 23+35 = 58
Mr de CaO > 1 x Ar Ca = 40 ~ 1 x Ar O = 16 ~ 40+16 = 56
Mr C6H12O6 > 6 x Ar C = 12 ~ 12 x Ar H = 1 ~ 6 x Ar O = 16 ~ 72+12+96 = 180
Mr HNO > 1 x Ar H = 1 ~ 1 x Ar N = 14 ~ 1 x Ar O = 16 ~ 1+14+16 = 31