Abacus (soroban)

Learning objectives

To illustrate the principles of the base ten system.
To illustrate the rule of complements of 5 and 10.
To visualize carrying over.

This animation represents the Japanese abacus (soroban). Balls are strung along rods (columns). Each rod corresponds, going from right to left, to ones, tens, hundreds, thousands…

The upper balls have a value of 5. The lower ones have a value of 1. In other words, an upper ball on the third rod from the right has a value of 5 hundreds (500).

A lower ball on the second rod from the right has a value of ten (10).

A ball is only counted when it has been moved down to the transverse (horizontal) bar.