There are 2 ways to enter a number in the virtual soroban:
Each column of the Japanese abacus can represent a number from 0 to 9. When the abacus is set to 0, all bottom deck beads are aligned at the bottom and the top deck beads are aligned at the top.
Within a single column, each bottom deck bead is worth 1 and the top deck one is worth 5.
Moving up 1 bottom deck bead increases by 1 the number represented in the column. Moving down the top deck bead increases the number by 5
For example, to represent the number 8 (5+3):
Multiple digit numbers are written left to right. Start from the leftmost digit and add each number to the corresponding column. If, for example you want to enter 739: