((1.25)/(2.5))=((3.8)/(x)).
((1.25)/(2.5))=((3.8)/(x))．
<gadget id="calculator">3.8 * 2.5</gadget>
<output>9.5</output>

<gadget id="calculator">9.5 / 1.25</gadget>
<output>7.6</output>

<result>7.6</result>