(1-(3/10)/(6/7))*(10/13).
(1-(3/10)/(6/7))*(10/13)．
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">6 / 7</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">(3/10) / (6/7)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">1 - (7/20)</gadget>
<output>13/20 = around 0.65</output>

<gadget id="calculator">10 / 13</gadget>
<output>10/13 = around 0.769231</output>

<gadget id="calculator">(13/20) * (10/13)</gadget>
<output>1/2 = around 0.5</output>

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