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

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/2) + (1/3) + (1/5)</gadget>
<output>61/30 = around 2.033333</output>

<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">(1/2) + (1/3) + (1/5) + (1/7)</gadget>
<output>247/210 = around 1.17619</output>

<gadget id="calculator">(61/30) * (247/210)</gadget>
<output>15_067/6_300 = around 2.391587</output>

<gadget id="calculator">1 + (1/2) + (1/3) + (1/5) + (1/7)</gadget>
<output>457/210 = around 2.17619</output>

<gadget id="calculator">(1/2) + (1/3) + (1/5)</gadget>
<output>31/30 = around 1.033333</output>

<gadget id="calculator">(457/210) * (31/30)</gadget>
<output>14_167/6_300 = around 2.24873</output>

<gadget id="calculator">(15_067/6_300) - (14_167/6_300)</gadget>
<output>1/7 = around 0.142857</output>

<result>1/7 = around 0.142857</result>