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sum ABCD +BCDA+CDAB+DABC, when each number has least prime divisor 11

Source: Mathematics Regional Olympiad of Mexico West 2018 P4

September 8, 2022
number theory

Problem Statement

The letters A,B,CA,B,C and DD each represent a different digit, so each of the four-digit numbers ABCDABCD, BCDABCDA, CDABCDAB and DABCDABC satisfy that its least prime divisor is equal to 1111. Determine all possible values of the sum ABCD+BCDA+CDAB+DABCABCD +BCDA+CDAB+DABC and for each possible value of said sum, give an example of a choice of digits A,B,CA,B,C and DD with which to obtain that value and which satisfies the conditions established above.