Summary
In a 1975 essay, Martin Gardner presented a trick for multiplying two large numbers, when one of the numbers was given by the operator. The explanation of trick involved factoring a number that was one more than a power of ten, thereby obtaining one of the factors being multiplied. In this paper, we explain how to choose one of the factors without needing the factorization step.
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No potential conflict of interest was reported by the author(s).
Additional information
Notes on contributors
Crystal Brubaker
Crystal Brubaker is a high school math teacher. She received her B.S. in Mathematics from Bridgewater College (2015) and her M.Ed. in Curriculum and Instruction from the University of Virginia (2016). In addition to teaching, she plays piano, accompanying local student choral ensembles, musical theater performances, and church services.
Verne Leininger
Verne Leininger (MR Author ID: 649092) is an associate professor and chair of the department of Mathematics and Computer Science at Bridgewater College in Virginia. He enjoys doing mathematical research with students. When not doing math, he breeds, raises, shows, and occasionally teaches a first year seminar class on chickens.