There are 5 rabbits in total, and every two of them dance once, how many times will they dance in total?
一共有5只兔子，每两只跳一次舞，一共要跳几次呢？
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">4 * (5/2)</gadget>
<output>10</output>

<result>10</result>