Five small partners are engaged in an arm wrestling competition. If each person is required to wrestle with other small partners once, how many arm wrestling competitions will there be in total?
5个小伙伴进行掰手腕比赛，如果要求每人与其他小伙伴掰一场，那么掰手腕比赛一共要比多少场．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<result>10</result>