(1+(1/5)+(1/6)+(1/7))*((1/5)+(1/6)+(1/7)+(1/8))-(1 +(1/5)+(1/6)+(1/7)+(1/8))*((1/5)+(1/6)+(1/7)).
(1+(1/5)+(1/6)+(1/7))*((1/5)+(1/6)+(1/7)+(1/8))-(1+(1/5)+(1/6)+(1/7)+(1/8))*((1/5)+(1/6)+(1/7))．
<gadget id="calculator">5 / 1</gadget>
<output>5</output>

<gadget id="calculator">6 / 1</gadget>
<output>6</output>

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

<gadget id="calculator">1 + 5 + 6 + 7</gadget>
<output>19</output>

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

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

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

<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/5) + (1/6) + (1/7)</gadget>
<output>107/210 = around 0.509524</output>

<gadget id="calculator">(1/8) - (107/210)</gadget>
<output>-323/840 = around -0.384524</output>

<gadget id="calculator">(1/5) + (1/6) + (1/7) + (-323/840)</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 / (1/8)</gadget>
<output>8</output>

<gadget id="calculator">5 + 6 + 7 + 8</gadget>
<output>26</output>

<gadget id="calculator">19 * 26</gadget>
<output>494</output>

<gadget id="calculator">1 + 5 + 6 + 7 + 8</gadget>
<output>27</output>

<gadget id="calculator">5 + 6 + 7</gadget>
<output>18</output>

<gadget id="calculator">27 * 18</gadget>
<output>486</output>

<gadget id="calculator">494 - 486</gadget>
<output>8</output>

<result>1/8 = around 0.125</result>