Arrange the digits 9, 4, 6, 3 in descending order for the greatest number: 9, 6, 4, 3 &rarr; 9643.<br><br>
&bull; For the second greatest, swap the last two digits of the greatest number.<br>
&bull; Keep 9, 6, then swap 4 and 3 &rarr; 9634.<br>
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Final Answer: 9634