The average of two numbers is 135, one of which is 102, what is the other number.
两个数的平均数是135，其中一个数是102，另一个数是多少．
<gadget id="calculator">135 * 2</gadget>
<output>270</output>

<gadget id="calculator">270 - 102</gadget>
<output>168</output>

<result>168</result>