Three people plant trees, the number of trees planted by A accounts for (2/5) of the total number of trees planted by B and C, and the number of trees planted by A accounts for ((())/(())) of the total.
三人植树，甲植树棵数占乙丙总数的(2/5)，甲植树棵数占总数的((())/(()))．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 + (2/5)</gadget>
<output>7/5 = around 1.4</output>

<gadget id="calculator">(2/5) / (7/5)</gadget>
<output>2/7 = around 0.285714</output>

<result>2/7 = around 0.285714</result>