If a man has a mass of 83 kilograms on earth what will the force of gravity on his body be in the moon

The man's mass doesn't change, no matter where he is.

Weight = (mass) x (gravity)

The acceleration due to gravity on the Moon is about 1.62 m/s² .

Weight of 83 kg on the Moon = (83 kg) x (1.62 m/s²) =  134.7 newtons

                                                                         (about 30.3 pounds)