The number A is 15, the number B is 3 times more than the number A, and the number B is more than the number A.
甲数是15，乙数比甲数的2倍多3，乙数比甲数多多少．
<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<gadget id="calculator">3 - 15</gadget>
<output>-12</output>

<gadget id="calculator">30 + (-12)</gadget>
<output>18</output>

<result>18</result>