Calculation: 1000+999-998+997+996-995+...+103+102-101=how much.
计算：1000+999-998+997+996-995+…+103+102-101=多少．
<gadget id="calculator">102 - 101</gadget>
<output>1</output>

<gadget id="calculator">1_001 + 103 + 1</gadget>
<output>1_105</output>

<gadget id="calculator">300 / 2</gadget>
<output>150</output>

<gadget id="calculator">1_105 * 150</gadget>
<output>165_750</output>

<result>165_750</result>