If (4/5) of a number is 80, what is (5/4) of this number.
如果一个数的(4/5)是80，那么这个数的(5/4)是多少．
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">80 / (4/5)</gadget>
<output>100</output>

<gadget id="calculator">5 / 4</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">100 * (5/4)</gadget>
<output>125</output>

<result>125</result>