Abacus 2026

How to use the abacus

• Move beads toward the center bar to count them.
• Classic 2:5 provides two upper beads and five lower beads per rod.
• Modern Soroban 1:4 uses one upper bead and four lower beads per rod.
• The Decimal selector adds tenths or hundredths rods to the right of the ones rod. A glowing marker identifies the decimal boundary.
• Build starts at zero, Add loads the first number, and Subtract loads the starting number.
• A completion effect appears when the displayed value matches the target.
• Use Lesson for guided explanations of place value, addition, subtraction, carrying, and borrowing.
• Use the Places button to view the place-value table. Shape, Finish, sound, and volume controls remain in the main panel.
• Options provides larger text, reduced motion, teacher display mode, timed practice, recent session history, and a Restore Defaults control.
• Keyboard shortcuts: N creates a problem, H gives a hint, P opens Places, L opens Lessons, and R resets.