The moon is not made of green cheese
My suggestion is we know very little about the actual moon orbiting our Earth.
The standard formula does not really apply.
For one thing, the surface indicates lighter materials than that on the Earth. The core is less dense than the Earth possibly consisting of basalt rather than Iron/nickel. That having been said, I suggest that the moon is heavier than it is supposed to be for its size.
The size indicates a gravity of 1/6th that of the Earth. In theory, You should weigh approximately 16.7 pounds for every 100 pounds that you weigh here on Earth. I am suggesting that it is more likely that you might weigh in more around 20-22 pounds per 100 pounds on Earth. That doesn’t seem like much to me until you start dealing in tons of metal in a spaceship.
The important question is why? Over hundreds of millions of years the planet has been consistently bombarded by Nickel/Iron Core asteroids. So even though you have a basic core consisting of lighter metals, the Moon itself has been plastered with Iron from its beginning. That means the surface is actually heavier than the core. This is important because it means a huge variation in what things actually weigh from one portion of real estate to another.
Then there is what I call the Mercury effect. Mercury is an extremely dense object very close to the Sun. Temperature extremes are common from one side of the planet to the other. The moon has a 400 degree temperature range every two weeks. So naturally it is going to cook some of the lighter elements off its surface over time. All of this I believe gives the moon one of the denser surfaces of any moon in the Solar System with the possible exception of Io around Jupiter.
The effect of temperature extremes is on things like liquids. Deep in the Moon it is likely to be a swiss cheese effect. That means the Moon is probably also honeycombed with caves all the way to the core. What makes that interesting is we might have a ready fuel supply buried deep in the Moon. An alternate theory suggests that at some point in our past Oil rained over much of Planet Earth in a near collision with another planet with a much denser atmosphere. This would account for the stains all over the Moon’s surface originally thought to be oceans. I suggest they might be markers for where the oil drained into caves beneath the surface. If this is the case, then an atmosphere in the caves is entirely possible. This would form miniature biological atmospheres where life could actuall exist in primitive forms.
Further, I suggest the moon originated further out in the solar system and was dragged in by some object much larger than itself. This object might have side swiped our planet in its early history leaving the moon in its wake. If for instance the moon originated from around Saturn, it might have had a lot more water than it does today. That water might have leached off the Moon and would have been captured by the Earth over time.
You have a huge tidal effect from being constantly pulled between the Earth and the Sun. This would cause any liquids to eat through the surface and make for huge caverns deep in the moon. This is important because it would be easier to put a colony in those caverns than to build domes on the surface. You also have an enormous savings in materials. The question becomes where are the caverns and how deep under the surface are they?
I feel that caverns must be between 200 and 400 feet below the surface. That is adequate to provide plenty of insulation against the drastic temperature changes.
The profit will be in mining the fuels necessary to get to other planets.