(2/3) of 15 is equal to ((())/(())) of 80, and 35 is 30% less than that.
15的(2/3)等于80的((())/(()))，35比多少少30%．
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (3/10)</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">35 / (7/10)</gadget>
<output>50</output>

<result>50</result>