Adapted from https://www.wikihow.com/Use-an-Abacus

An abacus is a deceptively simple calculating tool that has been used for thousands of years. This short booklet has instructions on how to use an abacus to count, add, subtract, multiply, and divide numbers.

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Contents
How to Use an Abacus 
Counting Numbers Using an Abacus 
Part 1: Counting 
Part 2: Adding and Subtracting 
Part 3: Multiplying
Part 4: Dividing