2004-1999+200400/25/4.
2004-1999+200400/25/4．
<gadget id="calculator">2_004 - 1_999</gadget>
<output>5</output>

<gadget id="calculator">200_400 / 25 / 4</gadget>
<output>2_004</output>

<gadget id="calculator">5 + 2_004</gadget>
<output>2_009</output>

<result>2_009</result>