Calculation: 1+11+21+...+1991+2001+2011=how much.
计算：1+11+21+…+1991+2001+2011=多少．
<gadget id="calculator">1 + 2_011</gadget>
<output>2_012</output>

<gadget id="calculator">2_011 - 1</gadget>
<output>2_010</output>

<gadget id="calculator">2_010 / 10</gadget>
<output>201</output>

<gadget id="calculator">201 + 1</gadget>
<output>202</output>

<gadget id="calculator">202 / 2</gadget>
<output>101</output>

<gadget id="calculator">2_012 * 101</gadget>
<output>203_212</output>

<result>203_212</result>