((1+2+3+4+5+6+5+4+3+2+1)/(666666*666666)).
((1+2+3+4+5+6+5+4+3+2+1)/(666666*666666))．
<gadget id="calculator">1 + 2 + 3 + 4 + 5 + 6 + 5 + 4 + 3 + 2 + 1</gadget>
<output>36</output>

<gadget id="calculator">666_666 * 666_666</gadget>
<output>444_443_555_556</output>

<gadget id="calculator">36 / 444_443_555_556</gadget>
<output>1/12_345_654_321 = around 0</output>

<result>1/12_345_654_321 = around 0</result>