The proper word equation for
4Fe + 3Sn(NO3)4 = 4Fe(NO3)3 + 3Sn is as below
Iron + Tin (iv) nitrate = iron(iii) nitrate + Tin
iron displaces tin from it compound ( Tin (iv) nitrate to form iron (iii) nitrate and tin.
from the equation above 4 moles of Fe displaces 3 moles of Sn(NO3)4 to form 4 moles of Fe(NO3)3 and 3 moles of SN