An abacus, also referred to as a counting frame, is a device used to perform calculations. Abaci (or abacuses) can be used to teach arithmetic, perform practical calculations, and more.

People have been using abaci for thousands of years. Although many people use computers or calculators to perform calculations that abaci were primarily used for in the past, it is still not uncommon to find abaci being used today, particularly in certain parts of the world like Eastern Europe, Russia, China, and Africa.

There are a number of different types of abaci. In the past, abaci were made using things like beans or stones that people moved in grooves of sand, tablets of wood, or even metal. Today, they are more commonly made using bamboo frames that house beads that slide on wires. Below are a few examples of different abaci:

An abacus can be used to perform addition, subtraction, multiplication, and division. It is also possible to use an abacus to perform more complicated calculations such as square roots.

The methods for performing these calculations depend on the specific abacus used. Generally, each row or column in an abacus represents a place value such as the ones place, tens place, hundreds place, and so on. Using the first abacus with beads of a single color in each row, the black beads can be used to represent the ones place. In such a case, the dark blue beads directly above would be the tens place, the row above that the hundreds place, and so on. So in this abacus, we could represent the number 12 using one dark blue bead, and two black beads. For more detail on how to use an abacus to perform specific operations, reference specific videos for the respective abacus type, as describing how to perform basic operations on an abacus using text can be more confusing than helpful.