There are 7 girls lined up in a row, and now 2 boys are inserted into every 2 girls, how many boys are inserted in total?
有7名女生排成一排，现在每两名女生中插进2名男生，共插进多少名男生？
<gadget id="calculator">7 - 1</gadget>
<output>6</output>

<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<result>12</result>