There
are 28 pieces in a standard set of dominoes.
Each domino has two numbers on its face.
The
two numbers on 21 of the tiles differ.
These are referred to as singles
or singletons.
The
other 7 tiles repeat the same number twice on their faces. These are the doubles or doublets. In the figure below the 7 doublets comprise
the right-most column.
The
piece in the set with the most total dots is the 6-6 doublet, so sometimes a
standard set of dominoes is called a 6-6
set.
The standard 6-6
set of dominoes . . .
