Visual GCD

This worksheet demonstrates a visual algorithm for computing the greatest common divisor of two numbers. At each step, we cut off the largest possible square from the top right corner, until the shape that remains is a square. The side length of the final square is the greatest common divisor of the side lengths. Can you see why this works? I would like to thank the participants on the GeoGebra forum for helpful discussions while I was developing this worksheet.


David Radcliffe

Resource Type
algebra  exploration  lcm-and-gcd  number_theory 
Target Group (Age)
15 – 18
English (United Kingdom)
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