On October 21st of the Mystery Year, Abebe Bikila set a world marathon record. Clues for finding the year involve unit rate, proportions, measurement conversions, and reasoning skills. The sports context of this puzzle is a great motivator for sixth grade students and up. Your PDF download includes:2-page digital version with horizontal layout, prepped for Easel 1-page printable version3 pages of Teacher Notes including step-by-step Solutions, Extensions, and a variety of Professional Developmen