The fraction value is equal to (3/7), and what is the sum of all fractions whose denominator is less than 70 and greater than 40.
分数值等于(3/7)，而分母小于70且大于40的所有分数的和是多少．
<gadget id="calculator">27 / 63</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">24 / 56</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">21 / 49</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">18 / 42</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">(3/7) + (3/7) + (3/7) + (3/7)</gadget>
<output>12/7 = around 1.714286</output>

<result>12/7 = around 1.714286</result>