Mass and weight are affected by gravity on the Moon, but in different ways.

Mass: Mass is a measure of the amount of matter in an object. It is not affected by gravity. An object's mass is the same on Earth as it is on the Moon.

Weight: Weight is the force of gravity acting on an object. It is measured in newtons (N). The force of gravity is weaker on the Moon than it is on Earth, so objects weigh less on the Moon. A person who weighs 100 N on Earth would weigh only about 16.5 N on the Moon.

So, while mass is not affected by gravity, weight is. Objects weigh less on the Moon than they do on Earth because the force of gravity is weaker on the Moon.