Calculation: 3+6+9+12+15+...+96+99.
计算：3+6+9+12+15+…+96+99．
<gadget id="calculator">3 + 99</gadget>
<output>102</output>

<gadget id="calculator">99 / 3</gadget>
<output>33</output>

<gadget id="calculator">33 / 2</gadget>
<output>33/2 = around 16.5</output>

<gadget id="calculator">102 * (33/2)</gadget>
<output>1_683</output>

<result>1_683</result>