(1/21)+(303/2121)+(50505/212121)+(13131313/21212121)+(1414141414/2121212121).
(1/21)+(303/2121)+(50505/212121)+(13131313/21212121)+(1414141414/2121212121)．
<gadget id="calculator">1 / 21</gadget>
<output>1/21 = around 0.047619</output>

<gadget id="calculator">303 / 2_121</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">50_505 / 212_121</gadget>
<output>5/21 = around 0.238095</output>

<gadget id="calculator">13_131_313 / 21_212_121</gadget>
<output>13/21 = around 0.619048</output>

<gadget id="calculator">1_414_141_414 / 2_121_212_121</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(1/21) + (1/7) + (5/21) + (13/21) + (2/3)</gadget>
<output>12/7 = around 1.714286</output>

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