A number (4/5) is 160, what is 50% of this number?
一个数的(4/5)是160，这个数的50%是多少．
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">160 / (4/5)</gadget>
<output>200</output>

<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">200 * (1/2)</gadget>
<output>100</output>

<result>100</result>