2000-1+999*111*9.
2000-1+999*111*9．
<gadget id="calculator">2_000 - 1</gadget>
<output>1_999</output>

<gadget id="calculator">999 * 111 * 9</gadget>
<output>998_001</output>

<gadget id="calculator">1_999 + 998_001</gadget>
<output>1_000_000</output>

<result>1_000_000</result>