The gram is the basis of metric weight , a kilogram is just a lot of them obtained by moving the decimal point. You can do this anyway with any system of units if you want; surveyors have no problem with using decimals of a foot, and by doing so in no way detract from the usefulness of the inch as a unit of measure.

With a system of units, the quantity of one unit within a larger unit is not necessarily based on the base of your numbering system.