# Yossi Elran

Yossi Elran (Hebrew: יוסי אלרן; born October 1, 1967) is an educator, author, and expert in recreational mathematics and innovation in education. He is the head of the Innovation unit at the Davidson Institute of Science Education and the founder of the institute's online science communication programs and website. He also lectures on recreational mathematics, creative thinking and innovation in education. By training, he is a physical chemist.

## Biography

Yossi Elran was born in the United Kingdom as Joseph Godfrey. He immigrated to Israel at a young age and studied at the Netiv Meir Yeshiva.
Elran served in Unit 8200 in the Israel Defense Forces (IDF), reaching the rank of Major. He earned a bachelor's degree in chemistry from Bar-Ilan University, following which he pursued a direct-track PhD in theoretical chemistry. His doctoral dissertation, which he completed with highest honors in 2001 under the supervision of Kenneth Kay, dealt with semiclassical treatment of chemical reactions.
He did postdoctoral research with the guidance of David Tannor at Weizmann Institute of Science, and later with Paul Brumer at the University of Toronto, where he focused on the semiclassical treatment of decoherence. Upon returning to Israel in 2004, he joined the Davidson Institute of Science Education and in 2009 was appointed head of the Educational Technology Unit. In 2017, he briefly served as the acting director-general of the Davidson Institute before assuming his current role as head of the Innovation Unit.
Since 2020, Elran has served as a lecturer in the education department at the Western Galilee College, and during 2022–2023, he was a lecturer at the Shenkar College of Engineering and Design on the connection between mathematics and the Arts.

## Recreational Mathematics

Elran is a leading advocate for the use of recreational mathematics in math education. He developed a method where a puzzle serves as a trigger for a deeper journey into the underlying mathematics, using an associative approach inspired by his Talmudic studies under Rabbi Baruch Gigi at Yeshivat Har Etzion.
He is the creator of MOOCs in recreational mathematics, including the online courses "Math-by-Mail" and "Science-by-Mail" for young children. This course, initially developed at the Weizmann Institute in the late 1980s by Ruhama Even and Neta Maoz, was managed by Elran and his wife Michal, an expert in mathematical education, for nearly two decades until it became a full online MOOC for children in four languages, reaching up to 5,000 students annually at its peak.
Elran has developed original puzzles in recreational mathematics, including "Retrolife", and the unusual word search variations: "Prime Number Search" and "Greco-Latin Search", both of which appear in his book "Lewis Carroll’s Cats and Rats and Other Puzzles with Long Tales" along with other original puzzles.
Elran's associative-Talmudic method is reflected in this book where each chapter is dedicated to a puzzle through which readers "travel" through various mathematical topics. For example, the chapter on "The Number Pyramid " exposes readers to subjects like modular arithmetic, combinatorics, figurate numbers, fractals, and more, introducing readers to mathematicians from history such as Blaise Pascal and Carl Friedrich Gauss.
He created several paper puzzles (featured in "The Paper Puzzle Book," co-written with David Goodman and Ilan Garibi); contributed to the theory of flexagons; and devised mental calculator "Doomsday" rules for the Hebrew calendar. From 2007 to 2009, he wrote a monthly column on recreational mathematics titled "Jumping in Headfirst" with his wife Michal, published in the journal "Galileo".
Additionally, he collaborated with TED-Ed to develop adaptations for two well-known puzzles: the "Egg Drop Riddle" and the "Prisoner's Dilemma Riddle".
Elran is a long-time member of the Gathering 4 Gardner (G4G) organization, dedicated to the legacy of Martin Gardner, and he chaired the organization's "Celebration of Mind" committee for three years.

## Publications

* Elran, Yossi (2015). Lewis Carroll’s Cats and Rats and Other Puzzles with Long Tales. World Scientific Publishing Company.
* Elran, Yossi, Goodman, David, Garibi, Ilan (2018). The Paper Puzzle Book. World Scientific Publishing Company.