(0.25*4-0.25*3)*40.
(0.25*4-0.25*3)*40．
<gadget id="calculator">0.25 * 4</gadget>
<output>1</output>

<gadget id="calculator">0.25 * 3</gadget>
<output>0.75</output>

<gadget id="calculator">1 - 0.75</gadget>
<output>0.25</output>

<gadget id="calculator">0.25 * 40</gadget>
<output>10</output>

<result>10</result>