The abacus has four columns. Each column has a particular value. These are, from right to left, columns for ones, tens, hundreds and thousands. Use the abacus to visualise the structure of numbers and carry out mathematical calculations. The abacus can also be used in arithmetic to visualise exchanging and borrowing.
Press the cursor button in the toolbar to control the tool. Click on the plus symbol below a column to add a bead to that column. You can add a maximum of nine beads to a single column. If you add a tenth bead, the ten beads will automatically be exchanged for one unit in the next column to the left. You can add a maximum of nine beads to the column of thousands.
To remove a bead from the column, click on the minus symbol below the relevant column. You can also click on the minus symbol on the right of a column. In doing so, the particular unit is exchanged for ten smaller units and the bead is removed automatically.
Click on the settings button to adjust the tool settings. Adjust the information that is visible in the tool, such as column labels or values. Click on the settings button again or next to the settings menu to close the menu. You can reveal or hide numbers with the eye icon. Clear the abacus with the reset button.