How to enter a number in the Japanese abacus

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):

• On the first column, the rightmost, shift the top bead towards the center. This produces a 5.
• Move 3 of the bottom beads up towards the center. You have just added 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:

• Start by entering the number 7 in the third column starting from the right (move the top bead down and move 2 bottom beads up).
• Enter number 3 in the second column from the right (just move up 3 beads ot the bottom deck).
• Enter number 9 in the rightmost column (move the top bead down and all 4 bottom beads up).

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