The gravitation acceleration on the moon is different than on Earth. It is 1.6 m/s^2. If you weigh 120 lbs, then you would multiply 120 pounds by the gravitational acceleration on the moon and then divide by the acceleration on Earth.
(120 lbs * 1.6) / 9.8 = 20 pounds.
The mass will always be the same no matter what planet you’re on, so it’s still 54 kg.
