Calculation: (4/7)-(2/5)+(3/7)-(3/5).
计算：(4/7)-(2/5)+(3/7)-(3/5)．
<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(4/7) - (2/5)</gadget>
<output>6/35 = around 0.171429</output>

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

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(3/7) - (3/5)</gadget>
<output>-6/35 = around -0.171429</output>

<gadget id="calculator">(6/35) + (-6/35)</gadget>
<output>0</output>

<result>0</result>