2x-((x-1)/2)=2+((x+1)/2), x=how much.
2x-((x-1)/2)=2+((x+1)/2)，x=多少．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) - (1/2)</gadget>
<output>0</output>

<gadget id="calculator">2 + 0</gadget>
<output>2</output>

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

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

<result>2</result>