The number A is 18, and the number B is 5 less than twice the number A, what is the number B?
甲数是18，乙数比甲数的2倍少5，乙数是多少．
<gadget id="calculator">18 * 2</gadget>
<output>36</output>

<gadget id="calculator">36 - 5</gadget>
<output>31</output>

<result>31</result>