4. Calculate the gravity force between the Earth (m = 6*10^24 Kg) and the Moon (m = 7*10^22 Kg) when their distance is 4*10^8 m. (use G = 7*10^-11 Nm2/Kg2)

Fg = 1.8 * 10^52 N

the answer is given, but can someone explain how to get it?? I've tried for an hour to figure it out, but I am not getting it