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.
Click on a ball in order to slide it.
Click on the "labels" button (three horizontal lines inside a circle) on the navigation bar to show or hide the values.