There are 5 people in A, B, C, D, and E. Choose 2 people to form a mutual aid learning group. How many ways are there to form it?
有A，B，C，D，E5人，任选2人组成互助学习小组，共有几种组成方法？
<gadget id="calculator">4 + 3 + 2 + 1</gadget>
<output>10</output>

<result>10</result>