Welcome to the abacus.
0
Enter two numbers. The abacus sets the first number, then works each digit and explains every bead move.
to
Counts one bead at a time from the first number to the second, saying each number out loud. Reverse counts backwards.
Lessons
Start anywhere. Each lesson solves on the abacus with full explanation.
Move the beads yourself to work out the answer, then press Done? to check the abacus.