(1/2)+((1/3)+(2/3))+((1/4)+(2/4)+(3/4))+...((1/40)+(2 /40)+…+(38/40)+(39/40))
(1/2)+((1/3)+(2/3))+((1/4)+(2/4)+(3/4))+…((1/40)+(2/40)+…+(38/40)+(39/40))
<gadget id="calculator">0.5 + 19.5</gadget>
<output>20</output>

<gadget id="calculator">39 / 2</gadget>
<output>39/2 = around 19.5</output>

<gadget id="calculator">20 * (39/2)</gadget>
<output>390</output>

<result>390</result>