Calculation: 1+3+5+...+15+17.
计算：1+3+5+…+15+17．
<gadget id="calculator">1 + 17</gadget>
<output>18</output>

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

<gadget id="calculator">18 * (9/2)</gadget>
<output>81</output>

<result>81</result>