Question 1178646
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There is no fancy mathematics involved in solving this problem.  Do it yourself.<br>
(1) a is divisible by 4.  What are the possible values of a?
(2) ab is divisible by 5, so a is either 0 or 5.  From (1) and (2), what are the possibilities for the string ab?
(3) abc is divisible by 6.  For each of the possible strings ab, what digit(s) c make abc divisible by 6?
(4) For the possible strings abc from steps (1) to (3), what digit(s) make abcd divisible by 7?<br>