If x/2=15, then 200-3x=how much.
如果x/2=15，那么200-3x=多少．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">15 / (1/2)</gadget>
<output>30</output>

<gadget id="calculator">3 * 30</gadget>
<output>90</output>

<gadget id="calculator">200 - 90</gadget>
<output>110</output>

<result>110</result>