Vertical abacus

Vertical Abacus is an engaging Chrome extension designed for children and the elderly to learn numbers easily and enjoyably using Montessori color principles. It features an interactive vertical abacus where users can tap to add or remove balls, simulating counting on a physical abacus with intuitive visual cues.

Key features include automatic carry-over when reaching ten in a column, toggling between addition and subtraction modes, and buttons for generating random numbers or resetting. Users can also increment or decrement units with arrows, including fast forward and rewind through press-and-hold controls. The tool helps learners grasp numerical concepts ranging from units and tens up to thousands and tens of thousands, supporting foundational arithmetic skill-building with addition and subtraction exercises, along with a result check button for practice verification.