The three classes of the third grade donated an average of 168 yuan, and the first and second classes donated a total of 386 yuan. How much is the donation of the third class of the third grade?
三年级三个班平均捐款168元，一、二两班共捐款386元，求三年级三班捐款多少元？
<gadget id="calculator">168 * 3</gadget>
<output>504</output>

<gadget id="calculator">504 - 386</gadget>
<output>118</output>

<result>118</result>