What is the sum of all the proper fractions whose denominator is 6?
分母是6的所有真分数的和是多少．
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">2 / 6</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">3 / 6</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">4 / 6</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">(1/6) + (1/3) + (1/2) + (2/3) + (5/6)</gadget>
<output>5/2 = around 2.5</output>

<result>5/2 = around 2.5</result>