Calculation: (7/10)-((3/7)-(3/10)).
计算：(7/10)-((3/7)-(3/10))．
<gadget id="calculator">7 / 10</gadget>
<output>7/10 = around 0.7</output>

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

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(3/7) - (3/10)</gadget>
<output>9/70 = around 0.128571</output>

<gadget id="calculator">(7/10) - (9/70)</gadget>
<output>4/7 = around 0.571429</output>

<result>4/7 = around 0.571429</result>