Calculate with a simple method: (2/13)-(1/2)+(11/13).
用简便方法计算：(2/13)-(1/2)+(11/13)．
<gadget id="calculator">2 / 13</gadget>
<output>2/13 = around 0.153846</output>

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

<gadget id="calculator">(2/13) - (1/2)</gadget>
<output>-9/26 = around -0.346154</output>

<gadget id="calculator">11 / 13</gadget>
<output>11/13 = around 0.846154</output>

<gadget id="calculator">(-9/26) + (11/13)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>