(23+x+18)/2=30．
(23+x+18)/2=30．
<gadget id="calculator">23 / 2</gadget>
<output>23/2 = around 11.5</output>

<gadget id="calculator">18 / 2</gadget>
<output>9</output>

<gadget id="calculator">30 - (23/2) - 9</gadget>
<output>19/2 = around 9.5</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(19/2) / (1/2)</gadget>
<output>19</output>

<result>19</result>