From the 2002 numbers of 1, 2, 3, 4, ..., 2002, add any 21 numbers, how many different sums are there?
从1、2、3、4、…、2002这2002个数中，任取21个数相加，共有多少种不同的和．
<gadget id="calculator">2_002 + 1_982</gadget>
<output>3_984</output>

<gadget id="calculator">21 / 2</gadget>
<output>21/2 = around 10.5</output>

<gadget id="calculator">3_984 * (21/2)</gadget>
<output>41_832</output>

<gadget id="calculator">41_832 - 231</gadget>
<output>41_601</output>

<gadget id="calculator">41_601 + 1</gadget>
<output>41_602</output>

<result>41_602</result>