0.4*99+0.4．
0.4*99+0.4．
<gadget id="calculator">0.4 * 99</gadget>
<output>39.6</output>

<gadget id="calculator">0.4 * 1</gadget>
<output>0.4</output>

<gadget id="calculator">39.6 + 0.4</gadget>
<output>40</output>

<result>40</result>