If x+5=16, 2x-7=how much.
若x+5=16，2x-7=多少．
<gadget id="calculator">16 - 5</gadget>
<output>11</output>

<gadget id="calculator">2 * 11</gadget>
<output>22</output>

<gadget id="calculator">22 - 7</gadget>
<output>15</output>

<result>15</result>