Decim

A decim is a unit of currency representing a portion of a credit, the monetary unit of the United Federation of Planets in the 23rd century.

Values
In the 2260s, during shore leave on Capory, Leonard McCoy purchased an alcoholic beverage at the Last Chance/First Chance tavern. It was 7.5 credits, and he paid using a gold coin representing 10 credits. The bartender provided change, though he was 10 decims short.