2.5/((17.2-4.5*3.6)/0.04).
2.5/((17.2-4.5*3.6)/0.04)．
<gadget id="calculator">4.5 * 3.6</gadget>
<output>16.2</output>

<gadget id="calculator">17.2 - 16.2</gadget>
<output>1</output>

<gadget id="calculator">1 / 0.04</gadget>
<output>25</output>

<gadget id="calculator">2.5 / 25</gadget>
<output>0.1</output>

<result>0.1</result>