13.8-3.8/(2/5).
13.8-3.8/(2/5)．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">3.8 / (2/5)</gadget>
<output>9.5</output>

<gadget id="calculator">13.8 - 9.5</gadget>
<output>4.3</output>

<result>4.3</result>