Author:
Mingus Tabitha T. Y.,Grassl Richard
Abstract
Two recent problems appearing in die September 1997 and September 1999 issues of the NCTM publication Mathematics Teacher asked the following:A. An integer is called decreasing if each digit is less than the one to its left. Determine the number of decreasing integers between 2000 and 7000.B. A 5-digit integer is a peak number if its digits strictly increase to the middle one then strictly descend. Determine the number of 5-digit peak numbers that are greater than 70,000.
Publisher
Cambridge University Press (CUP)
Cited by
1 articles.
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1. 89.78 Extended peak numbers;The Mathematical Gazette;2005-11