10 girls stand in a row, every 2 girls jump in line and 3 boys jump in, how many boys jump in total.
10名女生站成一排，每隔2名女生插队3名男生，共插队多少名男生．
<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">3 * 4</gadget>
<output>12</output>

<result>12</result>