(2/7) how many such fractional units are added is equal to the smallest prime number.
(2/7)增加多少个这样的分数单位就等于最小的质数．
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">2 - (2/7)</gadget>
<output>12/7 = around 1.714286</output>

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

<gadget id="calculator">(12/7) / (1/7)</gadget>
<output>12</output>

<result>12</result>