Find the rules and fill in the numbers. 2, 6, 12, 20, how much.
找规律填数．2，6，12，20，多少．
<gadget id="calculator">8 + 2</gadget>
<output>10</output>

<gadget id="calculator">20 + 10</gadget>
<output>30</output>

<result>30</result>