The domino is a simple, thumbsized rectangular block that bears one to six pips or dots. A complete set contains 28 such pieces. A domino is the fundamental building block of a variety of games played with them. They are arranged in lines and angular patterns to form shapes or are laid on top of each other to create larger structures such as pyramids or mazes. The games may be competitive or cooperative and can involve strategy, luck, skill, or chance.

Dominoes can be a fun way to teach students the concept of addition and subtraction. The fact that the total number of dots on a domino does not change when it is oriented differently also helps to reinforce the commutative property of addition. It is also a good exercise in the development of spatial reasoning skills as students arrange the dominoes in various ways to build their understanding of the commutative property of addition.

Lily Hevesh began playing with dominoes as a child when her grandparents gave her their classic 28-piece set. She liked to set them up in straight or curved lines, then flick them so the whole line would fall. But it takes more than just a flick to get a domino to move, because the pieces have “inertia,” a tendency to resist motion unless some outside force pushes on them.

Even then, not all dominoes will fall the same way, since each piece has its own unique combination of pips or dots on its ends. Some are a single color; others have multiple colors; still others are shaped like arrowheads or hearts. Each type has its own rules for how it can be used in a game.

There are many different games that can be played with dominoes, but the most common involves scoring points by laying dominoes end to end (the touching ends must match, i.e., one’s touch one’s, two’s touch two’s, and so on). If the dominoes in a player’s opponent’s hands total a multiple of five, that player scores those points. Normally, play stops when a player places his or her last domino. The winners are the players or teams whose combined sum of all the dots remaining in their opponents’ hands is lowest.

The game can be extended with progressively larger sets, adding additional pips or dots to the ends of the dominoes. The most commonly used extended sets are double-twelve (91 tiles), double-nine, and double-15. Even with these enlarged numbers of dominoes, the maximum number of possible combinations of ends and thus of different games is limited by the amount of space available on a table for arranging them. Fortunately, the game is easy to transport and can be played virtually anywhere. As a result, it is a popular activity in schools and other settings. In the future, scientists hope to find more complex and interesting ways to use dominoes in education, such as arranging them to make a mathematical model or using them to illustrate the principles of physics.