满足A⊆{a，b，c}且A∩{a，b}={a}的集合A的个数有 ______．

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答案

∵A⊆{a，b，c}，

且A∩{a，b}={a}

∴a∈A，且b∉A

则满足条件的A有：

{a}，{a，c}

故答案：2

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