Two brothers collect stamps. The elder brother has three times as many stamps as the younger brother. If the elder brother gives the younger brother 18 stamps, the two have the same number of stamps. How many stamps does the older brother have?
兄弟俩集邮，哥哥的邮票数是弟弟的3倍，若哥哥拿18张给弟弟，则两人的邮票同样多，那么哥哥原来有多少张邮票．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">18 * 1 * 3</gadget>
<output>54</output>

<result>54</result>