There are 12 primary school students standing in a row, and it is required to place 2 pots of flowers between every two primary school students, how many pots need to be placed.
有12名小学生站成一排，要求在每两名小学生中间放2盆花，需要摆放多少盆．
<gadget id="calculator">12 - 1</gadget>
<output>11</output>

<gadget id="calculator">2 * 11</gadget>
<output>22</output>

<result>22</result>