1995-1+2-3+4-5+...+1948-1949=how much.
1995-1+2-3+4-5+…+1948-1949=多少．
<gadget id="calculator">975 * 975</gadget>
<output>950_625</output>

<gadget id="calculator">1_995 - 950_625</gadget>
<output>-948_630</output>

<gadget id="calculator">975 * 974</gadget>
<output>949_650</output>

<gadget id="calculator">(-948_630) + 949_650</gadget>
<output>1_020</output>

<result>1_020</result>