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Italian Mathematical Olympiad 2001 - Problem 4

Source:

November 4, 2012
least common multiplenumber theory proposednumber theory

Problem Statement

A positive integer is called monotone if has at least two digits and all its digits are nonzero and appear in a strictly increasing or strictly decreasing order.
(a) Compute the sum of all monotone five-digit numbers. (b) Find the number of final zeros in the least common multiple of all monotone numbers (with any number of digits).