What is the (2/5) increase and decrease (2/5) of 50 kg?
50千克增加它的(2/5)再减少它的(2/5)是多少．
<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">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">50 * (7/5) * (3/5)</gadget>
<output>42</output>

<result>42</result>