Mental abacus
The abacus system of mental calculation is a system where users mentally visualize an abacus to carry out arithmetical calculations. No physical abacus is used; only the answers are written down.
The abacus system of mental calculation is a system where users mentally visualize an abacus to carry out arithmetical calculations. No physical abacus is used; only the answers are written down.
The abacus system of mental calculation is a system where users mentally visualize an abacus to carry out arithmetical calculations. No physical abacus is used; only the answers are written down.
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