There are 10 suites of rooms on each floor of a building in a hotel. The rooms are numbered 1, 2, ..., 10 from the first floor, and continue to be numbered floor by floor (the room numbers of the second floor are 11, 12, ..., 20, etc.), now we know that Lao Wang and Lao Zhang both live in the building, Lao Wang's floor number is just equal to Lao Zhang's room number, and the sum of their room numbers is equal to 239, and Lao Wang's room number how many?
某旅馆的一座楼每层都有10套房间，房间自第一层开始依次编为1，2，…，10号，并逐层依次续编下去(第二层的房号为11，12，…，20，如此等等)，现知老王和老张都住在楼内，老王的层号刚好等于老张的房号，而他们的房号之和等于239，老王的房号是多少？
<gadget id="calculator">22 - 1</gadget>
<output>21</output>

<gadget id="calculator">10 * 21</gadget>
<output>210</output>

<gadget id="calculator">11 * 22</gadget>
<output>242</output>

<gadget id="calculator">249 - 242</gadget>
<output>7</output>

<gadget id="calculator">210 + 7</gadget>
<output>217</output>

<result>217</result>