Question 1210235
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Suppose the set S is {N}, where N is an even integer.<br>
The nonempty set {N} is a subset of the given set S, and the sum of the elements of that nonempty subset is divisible by 2.<br>
So the set {N} satisfies all the conditions; so the smallest number of elements a set must contain to satisfy the conditions is 1.<br>
ANSWER: 1<br>