Calculation: (1/2)-(3/7)+(5/9).
计算：(1/2)-(3/7)+(5/9)．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">(1/2) - (3/7)</gadget>
<output>1/14 = around 0.071429</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">(1/14) + (5/9)</gadget>
<output>79/126 = around 0.626984</output>

<result>79/126 = around 0.626984</result>