1+3+5+...+21=how much.
1+3+5+…+21=多少．
<gadget id="calculator">1 + 21</gadget>
<output>22</output>

<gadget id="calculator">21 - 1</gadget>
<output>20</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 + 1</gadget>
<output>11</output>

<gadget id="calculator">11 / 2</gadget>
<output>11/2 = around 5.5</output>

<gadget id="calculator">22 * (11/2)</gadget>
<output>121</output>

<result>121</result>