the author of this app says:
The Soroban is based on the Chinese Abacus which has 2 upper and 5 lower beads. The Japanese Soroban removed one upper and one lower bead since they were redundant for base 10 calculations.
The Soroban is an efficient calculating tool. It is also good exercise for your brain. The key to experiencing these benefits is frequent practice. 15 minutes a day, 5 days a week and you may experience some of the benefits such as increased concentration, greater memorization, and better mental math skills.
The Soroban engages the right side of the brain for math facts which is associated with long term memory, whereas rote memorization is a left brain activity and is more difficult to retain.
For a demonstration video see http://www.youtube.com/watch?v=WE08M9lNJ9M
- Realistic bead movement
- Configurable number of columns
- Column number indicators
- Scrollable columns (left and right)
- Zoom in and out
- Multiple bead color configurations
- Show current soroban value (standard mode)
- Shake reset
- Practice mode allows beginners to gradually improve fingering and number recognition.
- Exercise similar to Yomiagezan where a series of 10 numbers are presented with addition and subtraction calculations
- Yomiagezan activity features adjustable delay between numbers allowing a slower pace
- Requires iOS 2.2.1 or later