If 2.5x+3.8=16.3, then 3.5x-3.8=how much.
如果2.5x+3.8=16.3，那么3.5x-3.8=多少．
<gadget id="calculator">16.3 - 3.8</gadget>
<output>12.5</output>

<gadget id="calculator">12.5 / 2.5</gadget>
<output>5</output>

<gadget id="calculator">3.5 * 5</gadget>
<output>17.5</output>

<gadget id="calculator">17.5 - 3.8</gadget>
<output>13.7</output>

<result>13.7</result>