40% of a number is 40, what is the number (1/2).
一个数的40%是40，这个数是多少的(1/2)．
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">40 / (2/5) / (1/2)</gadget>
<output>200</output>

<result>200</result>