Solution ratio (5/6): (4/9)=(15/(x)).
解比例(5/6)：(4/9)=(15/(x))．
<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">15 * (4/9)</gadget>
<output>20/3 = around 6.666667</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">(20/3) / (5/6)</gadget>
<output>8</output>

<result>8</result>