There are a total of 28 dominoes in a standard set where the maximum number is six on each side, called a double-six set. Each domino is called a tile and the dots found on each of the tiles are called pips. For the standard 28-domino set, there are a total of 168 pips or dots.
Alternative names for the tiles are bones, cards, tickets, stones and spinners. Each domino is usually rectangular with a line dividing each side. Dominoes date back to the 13th century or earlier and were mentioned in writings from Chinese author Zhou Mi who mentioned dominoes, or "pupai," being sold by street vendors.
There are many different ways to play dominoes. The blocking game is the most common game for two players using a double-six set. The tiles are shuffled, each player draws seven and one player plays his or her first tile. Each player then extends the line of play with a tile from their hands. The game ends when one player plays all of their tiles or when the game is blocked due to the lack of plays available. If it becomes blocked, the player that blocks it receives all of the player points.
The formula for how many tiles are in a set is ((n+1)(n+2))/2, where n is the highest number found on a tile. A double-nine set of tiles contains a total of 55 tiles, a double-twelve set of tiles contains 91 tiles.