Find out the rules and fill them in. 3, 11, 20, 30, how much, 53.
找出规律，填一填．3，11，20，30，多少，53．
<gadget id="calculator">30 - 20</gadget>
<output>10</output>

<gadget id="calculator">20 - 11</gadget>
<output>9</output>

<gadget id="calculator">30 - 20 - 9</gadget>
<output>1</output>

<gadget id="calculator">30 + 10 + 1</gadget>
<output>41</output>

<result>41</result>