What is the sum of all the simplest proper fractions whose denominator is 4?
分母是4的所有最简真分数的和是多少．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(1/4) + (3/4)</gadget>
<output>1</output>

<result>1</result>