If there are 34 players playing on 12 table tennis tables, how many doubles players are there?
12张乒乓球台上共有34名运动员在打球，则双打运动员有多少名．
<gadget id="calculator">12 * 4</gadget>
<output>48</output>

<gadget id="calculator">48 - 34</gadget>
<output>14</output>

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

<gadget id="calculator">14 / 2</gadget>
<output>7</output>

<gadget id="calculator">12 - 7</gadget>
<output>5</output>

<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<result>20</result>