Outline Mathematics
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Peter glanced at the boy figuring. "Just a regular four-digit number," he said. "What's so very special about it? "Look, dad," Stan replied. "To divide it by seven you only have to drop its second digit." He was right, so what was the number? |
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Copyright © 1996-2012 Alexander Bogomolny
Solution
|
Peter glanced at the boy figuring. "Just a regular four-digit number," he said. "What's so very special about it? "Look, dad," Stan replied. "To divide it by seven you only have to drop its second digit." He was right, so what was the number? |
(In the applet below, click on the underlined omitted expressions. See what happens.)
Do not forget to check your solution.
References
- J. A. H. Hunter, Entertaining Mathematical Teasers, Dover Publications, 1983
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Copyright © 1996-2012 Alexander Bogomolny
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