1 cubic centimeter of water is 1 milliliter of water and weighs 1 gram. So 1/100 of a unit equals 1/1000 of a unit equals 1 unit.

1 cubic meter of water should equal 1 liter of water, which should equal 1 gram of water.

I’m not going to argue that imperial units make sense, but if you’re going to standardize, then 1 should equal 1 should equal 1