Calculation; 1*2*3+2*4*5+3*6*7+...+10*20*21.
计算；1*2*3+2*4*5+3*6*7+…+10*20*21．
<gadget id="calculator">10 + 1</gadget>
<output>11</output>

<gadget id="calculator">11 / 2</gadget>
<output>11/2 = around 5.5</output>

<gadget id="calculator">10 * (11/2)</gadget>
<output>55</output>

<gadget id="calculator">55 ** 2</gadget>
<output>3_025</output>

<gadget id="calculator">4 * 3_025</gadget>
<output>12_100</output>

<gadget id="calculator">2 * 10</gadget>
<output>20</output>

<gadget id="calculator">20 + 1</gadget>
<output>21</output>

<gadget id="calculator">21 / 6</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">10 * 11 * (7/2)</gadget>
<output>385</output>

<gadget id="calculator">2 * 385</gadget>
<output>770</output>

<gadget id="calculator">12_100 + 770</gadget>
<output>12_870</output>

<result>12_870</result>