5x-2+1.8=3.6.
5x-2+1.8=3.6．
<gadget id="calculator">3.6 - 1.8</gadget>
<output>1.8</output>

<gadget id="calculator">2 + 1.8</gadget>
<output>3.8</output>

<gadget id="calculator">3.8 / 5</gadget>
<output>0.76</output>

<result>0.76</result>