Calculation: 756+1478+346-(256+278)-246.
计算：756+1478+346-(256+278)-246．
<gadget id="calculator">256 + 278</gadget>
<output>534</output>

<gadget id="calculator">346 - 534 - 246</gadget>
<output>-434</output>

<gadget id="calculator">756 + 1_478 + (-434)</gadget>
<output>1_800</output>

<result>1_800</result>