What is the sum of all the numbers of natural numbers 1, 2, 3, ..., 105 (for example, the sum of the numbers of 98 is 17)
自然数1、2、3、…、105，所有数码之和为多少(如数98的数码之和为17)
<gadget id="calculator">1 + 9</gadget>
<output>10</output>

<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">10 * (9/2)</gadget>
<output>45</output>

<gadget id="calculator">45 * 10</gadget>
<output>450</output>

<gadget id="calculator">1 * 6</gadget>
<output>6</output>

<gadget id="calculator">1 + 2 + 3 + 4 + 5</gadget>
<output>15</output>

<gadget id="calculator">6 + 15</gadget>
<output>21</output>

<gadget id="calculator">450 + 450 + 21</gadget>
<output>921</output>

<result>921</result>