Dominoes are a game in which players try to make a line of dominoes fall by putting one tile on top of another, with the matching end touching each other. The lines can be straight, curved, grids that form pictures, or 3D structures like towers and pyramids. The game can be simple or elaborate, with a single player taking turns or paired up to play together. It can also be a competitive event, where builders create complex and imaginative domino effects or reactions before a live audience of fans.
Each domino is a rectangular piece of material such as wood or bone, normally twice the length of its width, with an identifying mark on each side. These identifiers, which are called pips or spots, are an arrangement of numbers similar to those on a die. The pips on the domino range from six to none or blank, and are separated by a line or ridge that divides the identity-bearing face visually into two squares, called ends.
The first player to place a domino must lay it so that its matching end touches the end of an already-existing tile or a corner of the domino table. The second player then places a domino that is adjacent to the first tile or touching it at its center or edge. This creates a chain of tiles that builds snake-like, depending on the game and the rules of play. A tile played to a double must be placed squarely on the edge of the domino table or perpendicular to it, so that the matching sides are touching fully.
In this activity, students use dominoes to explore addition. They can select dominoes at random, or choose those with a number on both ends to create an addition equation that shows the relationship between total dots and the number of matching dots. Students can then create a second equation showing the relationship between the number of dots on each side and the sum of those dots.
While dominoes can be used to learn basic addition, the game can also help students develop skills in geometry, measurement, data collection and analysis, and problem-solving. For example, students may notice that the number of dots on a domino and its match can be used to find the perimeter of a triangle, or that adding two equal-sided dominoes creates a line that crosses itself.
Students can also use a set of dominoes to explore the concept of time and sequencing. For example, students can work in pairs to create a sequence of dominoes that will build an elaborate structure, such as a tower or pyramid. When each pair of students has completed their sequence, they can measure the size of their structure and then compare it to a standard scaled model of the same structure. This helps students develop the sense of proportion and scale, as well as demonstrating the importance of planning and executing work carefully. This task also supports Mathematical Practice Standard 8, Look for and express regularity in repeated reasoning.