123+234+345-456+567+678+789-890=how many.
123+234+345-456+567+678+789-890=多少．
<gadget id="calculator">345 - 456</gadget>
<output>-111</output>

<gadget id="calculator">789 - 890</gadget>
<output>-101</output>

<gadget id="calculator">123 + 234 + (-111) + 567 + 678 + (-101)</gadget>
<output>1_390</output>

<result>1_390</result>