Simple calculation: 2999+2998+2997-2996-2995-2994+2993+2992+2991-2990-2989-2988+605+604+603-602-601-600.
简便计算：2999+2998+2997-2996-2995-2994+2993+2992+2991-2990-2989-2988+605+604+603-602-601-600．
<gadget id="calculator">2_997 - 2_996 - 2_995 - 2_994</gadget>
<output>-5_988</output>

<gadget id="calculator">2_991 - 2_990 - 2_989 - 2_988</gadget>
<output>-5_976</output>

<gadget id="calculator">603 - 602 - 601 - 600</gadget>
<output>-1_200</output>

<gadget id="calculator">2_999 + 2_998 + (-5_988) + 2_993 + 2_992 + (-5_976) + 605 + 604 + (-1_200)</gadget>
<output>27</output>

<result>27</result>